The Lion and Lamb in the Vision of John, who is he?
Question 1: In some of his books, Imam Ahmad al-Hassan interprets the twenty-four elders in the vision of John to be the twelve Imams and the twelve Mahdis pbut, mentioned in the Will of the Messenger of Allah Muhammad pbuhap . And the question is, who is the crucified lamb who was centered among them and whom they addressed?
Answer: Book of Revelation, Chapter 4:
 At once I was in the Spirit, and behold, a throne stood in heaven, with one seated on the throne .  And he who sat there had the appearance of jasper and carnelian, and around the throne was a rainbow that had the appearance of an emerald .  Around the throne were twenty-four thrones, and seated on the thrones were twenty-four elders, clothed in white garments, with golden crowns on their heads .  From the throne came flashes of lightning, and rumblings and peals of thunder ... ]
And in Chapter 5:  Then I saw in the right hand of him who was seated on the throne a scroll written within and on the back, sealed with seven seals .  And I saw a mighty angel proclaiming with a loud voice, “Who is worthy to open the scroll and break its seals?”  And no one in heaven or on earth or under the earth was able to open the scroll or to look into it,  and I began to weep loudly because no one was found worthy to open the scroll or to look into it .  And one of the elders said to me, “Weep no more; behold, the Lion of the tribe of Ju- dah, the Root of David, has conquered, so that he can open the scroll and its seven seals .”
 And between the throne and the four living creatures and among the elders I saw a Lamb standing, as though it had been slain, with seven horns and with seven eyes, which are the seven spirits of God sent out into all the earth .  And he went and took the scroll from the right hand of him who was seated on the throne .  And when he had taken the scroll, the four living creatures and the twenty-four elders fell down before the Lamb, each holding a harp, and golden bowls full of incense, which are the prayers of the saints.  And they sang a new song, saying, “Worthy are you to take the scroll and to open its seals, for you were slain, and by your blood you ransomed people for God from every tribe and language and people and nation,  and you have made them a kingdom and priests to our God, and they shall reign on the earth .”  Then I looked, and I heard around the throne and the living creatures and the elders the voice of many angels, numbering myriads of myriads and thousands of thousands,  saying with a loud voice, “Worthy is the Lamb who was slain, to receive power and wealth and wisdom and might and honor and glory and blessing!”  And I heard every creature in heaven and on earth and under the earth and in the sea, and all that is in them, saying, “To him who sits on the throne and to the Lamb be blessing and honor and glory and might forever and ever!”  And the four living creatures said, “Amen!” and the elders fell down and worshiped .]
In Chapter 14:  Then I looked, and behold, on Mount Zion stood the Lamb, and with him 144,000 who had his name and his Father’s name written on their foreheads ... ] 
From these passages, it is made clear to you that the one who was once symbolized as a lion and once as a slaughtered lamb is one of the twenty-four elders, as the one sitting on the throne is the one dominating the vision, and it is clear in the vision that he is the best of everyone in rank and superiority . And the twenty-four elders sitting on the thrones are the closest ones in rank to the one sitting on the throne, from among those present in the vision, as it is clear in the vision .
Therefore, the slaughtered lamb is not better than the one sitting on the throne, nor is he better than the twenty-four, although we see in the vision that he earned taking the scroll and opening the seals; so how did he earn taking the scroll without them, while they are closer than him and better than him?!
Therefore, the slaughtered lamb must be a symbol of one of the twenty-four elders .
As for the fact that they submitted to him and spoke to him ... etc, they submitted in the meaning that they prepared and paved the way, and they are believers in the result, which is applying the supremacy of Allah on His earth .
As for your saying that there is a problem with the fact that one of the twenty-four elders is the same one symbolized by the lamb and the lion, thus how would he address himself; and, in reality, this is hardly a problem, because we are talking about a vision; so, there is no problem that one of the twenty-four elders would address a side of his symbolized by the lamb, and another side symbolized by the lion, etc . And if this problem was valid, it would have been valid to negate the vision, because it symbolized he who has overcome and earned opening the scroll by the lion, and then clarified that the one who took the scroll is the slaughtered lamb .
 behold, the Lion of the tribe of Judah, the Root of David, has conquered, so that he can open the scroll and its seven seals .”  And between the throne and the four living creatures and among the elders I saw a Lamb standing, as though it had been slain, with seven horns and with seven eyes, which are the seven spirits of God sent out into all the earth .  And he went and took the scroll from the right hand of him who was seated on the throne .]
Therefore, the slaughtered lamb and the lion are symbols of who has overcome and earned taking the scroll and opening its seals, and he is one of the twenty-four elders . So in the rank of overcoming, which requires strength, bravery and dedication, he was symbolized by the lion . And in the rank of taking the seals, which requires sacrifice, he was symbolized by a lamb standing as if it had been slaughtered . And both sides belong to the same person. And there is no inconsistency between them, as the strength of the spirit is a result of the sacrifice, sincerity and patience upon receiving injustice .
As for their interpretation of the slaughtered lamb in the vision to be Jesus pbuh, it is negated by the fact that according to them the one sitting on the throne is Allah, He is far above that. 
And it is not hidden that this interpretation of theirs restricts Allah swt and negates His absolute divinity . And for further details, you can read The Book of Monotheism .
While to us the one sitting on the throne is Muhammad pbuhap, and around him are twenty-four elders also on thrones, and they are the vicegerents of Allah on His earth, the Imams and the Mahdis mentioned by the Messenger of Allah pbuhap in his sacred will .
 Concerning the mentioned number of 144,000, whose foreheads are sealed by the name of the lamb and his Father’s name, some of the clerics of the Church have said, “We, before the Church, are the people of God . It includes a very large number . It also includes a great audience from every nation and every tribe and every people and every tongue . They are four words, and this is what is meant by the world with its four ends .” And when the number men- tioned in the vision was too little to be concerning their interpretation, they said, “The number is a symbolic number” only and it is not really intended . They said that with all coldness, as the interpretation with no proof is easily provided by them . Refer to Studies in The Holy Book, the Revelation of St.John by Paul Feghali
 The fact that the different symbols of the vision indicate the same person from different sides is a matter also believed in by the Christian clerics, and as an example, I mention two texts . One of them is by Father Antonios Fekry, saying, “He is a lion in his strength and his sovereignty is over us and over all the creation, but he is a lamb in how he presented himself for slaughter on the cross and his bearing of our sins. ”The Explanation of the Holy Book, the New Testament, the Interpretation of Revelation 5 .
And the other text is by Dr . William MacDonald, he says, “In the Book of Revelation, our Lord is represented as a lamb and a lion together . So from one side, the fact that he is the lamb of God thus he is the slaughtered lamb that lifts the sins of the world, and as the lion as he is the judge punishing his enemies . At his first coming he was the lamb (the sheep), and at his second coming he will be the lion .” Emmaus Bible College . And Father Paul Feghali says, “We waited for a lion so here we are before a lamb, why was Jesus called a lamb? There are three reasons ... ” Studies in The Holy Book, the Revelation of St. John .
 Concerning the one sitting on the throne, Dr . William MacDonald says, “God is seen holding a scroll with seven seals that protect it .” Emmaus Bible College . Likewise, Father Paul Feghali says, “And there was a throne established in the sky, this entire book is overseen by the word ‘throne’ . It is mentioned fourteen times, twice of which are in plural form as we see other thrones (the twelve) surrounding the first throne, the throne of God .” Studies in The Holy Book, the Revelation of St. John
 The Book of Monotheism by Imam Ahmad al-Hassan, in which he clarified the true belief in the divinity and he debated the false ideologies which many people believe in today, whether Muslims, Christians or otherwise .
 The sacred will that mentioned the twelve Imams and twelve Mahdis has been mentioned earlier in this book .