The ten horned beast in both Rev and Daniel are kingdoms, not an individual. Only the second beast, the FP, can be the AC. He is the supreme leader of the ten horned kingdom, ruling the world. No biblical writer ever described the AC and some other second in command person. Both the FP and Paul's man of sin perform miracles to deceive.
A global kingdom composed of ten smaller kingdoms on 7 areas of land is not a person. The ten horned beast isn't a person in Daniel, why would it be a person suddenly in Rev 13?
DANIEL 7:
24 And the ten horns out of this kingdom are ten kings that shall arise: and another shall rise after them; and he shall be diverse from the first, and he shall subdue three kings.
Well I agree that no biblical writer described the false prophet as second in command. they describe him as a religious leader that orders the world to worship the antichrist and wear his mark!
As for REvelation,
Revelation 13
King James Version
13 And I stood upon the sand of the sea, and saw a beast rise up out of the sea, having seven heads and ten horns, and upon his horns ten crowns, and upon his heads the name of blasphemy.
2 And the beast which I saw was like unto a leopard, and his feet were as the feet of a bear, and his mouth as the mouth of a lion: and the dragon gave him his power, and his seat, and great authority.
3 And I saw one of his heads as it were wounded to death; and his deadly wound was healed: and all the world wondered after the beast.
4 And they worshipped the dragon which gave power unto the beast: and they worshipped the beast, saying, Who is like unto the beast? who is able to make war with him?
5 And there was given unto him a mouth speaking great things and blasphemies; and power was given unto him to continue forty and two months.
6 And he opened his mouth in blasphemy against God, to blaspheme his name, and his tabernacle, and them that dwell in heaven.
7 And it was given unto him to make war with the saints, and to overcome them: and power was given him over all kindreds, and tongues, and nations.
Greek has a third person impersonal pronoun so according to the greek the antichrist is a he who is the first beast wqhom the dragon gives his power and authority to.
The dragon offered this once to another person who refused it!
Matthew 4:8-10
King James Version
8 Again, the devil taketh him up into an exceeding high mountain, and sheweth him all the kingdoms of the world, and the glory of them;
9 And saith unto him, All these things will I give thee, if thou wilt fall down and worship me.
10 Then saith Jesus unto him, Get thee hence, Satan: for it is written, Thou shalt worship the Lord thy God, and him only shalt thou serve.
Luke 4:6-8
King James Version
6 And the devil said unto him, All this power will I give thee, and the glory of them: for that is delivered unto me; and to whomsoever I will I give it.
7 If thou therefore wilt worship me, all shall be thine.
8 And Jesus answered and said unto him, Get thee behind me, Satan: for it is written, Thou shalt worship the Lord thy God, and him only shalt thou serve.
Gods son refuses it, but satans son will receive it and worship the dragon.