HereIam60, I'm not sure what they taught originally. I have lost track of Watchtower interpretation. Perhaps Duran knows.
Duran (I now know where you got your moniker from), I think I have identified your problem, why you want to sea the sea beast in Rev. 19. It boils down to the following:
1) "And it misleads those who dwell on the earth, because of the signs that were granted it to perform in the sight of the wild beast" (Rev. 13:14 NWT)
"and, by the signs he was permitted to perform on behalf of the beast" (Rev. 13:14 NET)
"the false prophet that performed in front of it the signs" (Rev. 19:20 NWT)
"the false prophet who had performed the signs on his behalf–" (Rev. 19:20 NET)
So which is it, "in sight of" or "on behalf of"? General consensus of the Dictionaries and Lexicons indicate the latter:
by the authority of, on behalf of Rv 13:12, 14; 19:20. Also simply by Lk 3:7 D (but s. 2a).—Johannessohn, Präpositionen 194-97; 359-61; AWikenhauser, Ἐνώπιος--ἐνώπιον--κατενώπιον: BZ 8, 1910, 263-70.—DELG s.v. ἐνῶπα. M-M. (BDAG).
by the authority of, on behalf of (RV 13.12, 14; 19.20) (Friberg).
at the instance of anyone, by his power and authority: Rev. 13:12,14; 19:20 (Thayer).
In Rev 13:12, 14; 19:20 ἐνώπιον τοῦ θηρίου ποιεῖν τι, do something "in the presence of the beast," is to be understood as "at the commissioning of the beast." (EDNT).
2) "and, by the signs he was permitted to perform on behalf of the beast" (Rev. 13:14 NET)
"the false prophet who had performed the signs" (Rev. 19:20 NET)
What signs?
13:14 = "even making fire come down from heaven" and "he deceived those who live on the earth" (Rev. 13:13, 14 NET)
19:20 = "which he deceived those who had received the mark of the beast and those who worshiped his image" (Rev. 19:20 NET)
Conclusion: The mark of the beast was introduced in the time of the new beast, and the new beast IMO is the scarlet beast (beast from the abyss).
That's enough for the time being. I will answer above questions later.