I don’t mind saying it, as truth is truth and whatever is supposed to happen, will happen, regardless of which school of thought you belong to.
I’m a SDA and that is my church’s position.
Some of those ideas are rather silly at this point, like EGW's claim that eeevvilll Rome is planning a vast end times persecution of everyone who worships on Saturday. Most Catholic parishes now have Sunday-anticipated Masses on Saturday night. I guess evil Rome is going to persecute ... herself?
Authentic Catholicism can "unite" with Islam only when Islam rejects their many errors. When we have an "Islam" that can say the Nicene Creed and believe it, then we can talk about "uniting" Catholicism and Islam, within one Catholic Church. Of course, they won't be Muslims anymore, when that happens.
As to what apostate Catholics may do in the future, most of them seem to obey Pope Zeitgeist. Maybe after they get bored with "ordaining" women and "marrying" homosexuals, they'll embrace Islam. Anything but actually embracing the truth ... see Lewis's Great Divorce in the scene with the Anglican prelate.