All the above said, by all the above people, cannot change Ent's perceiption one whit.
Ent stands on this:
1. There is no canonical text saying
Balrogs have wings.
2. There is one canonical text telling us a
Balrog was shrouded in
shadows like wings.
3. We are told those 'likenesses' later 'spread from wall to wall' or something like that. NOT that real wings spread from wall to wall.
Ent holds to the suspicion what the Text says does not support "real wings" - and all the other contrivances are just that - contrivances speculating into a possibility they COULD have had wings in some way or another.
Now... if I were to spread my billowing coat out from my body "like wings", and later those coat pieces looking "like wings" reached from wall to wall, would I have wings? No, I'd have parts of a billowing coat.
The Balrog had shadows. He didn't and couldn't fly. (he's not like an ostrich or any other winged creature who 'has wings' but can't fly, by the way, so please don't bring up ostriches with me. All
Durin's Bane had was shadows looking 'like wings.')
So... we remain with this subject just where we have always remained. There's what the canonical text says, which makes it clear there are shadows "like wings" - the syntax of the language does not allow for any other interpretation - then there are speculations about things written elsewhere. "Maybes" "Possiblys". "Could perhaps in some world or situation unspoken to, perhaps..."
In contrast to the concept they could routinely 'change their form, we also need to lay the fact
Sauron could no longer change his form... according to textual evidence. The Balrogs were different, though of lesser power? Again, we speculate greatly.
Ent will shut up now, and forever remain hooked to the text we KNOW, rather than the texts about which we must draw naught but speculations.
Were it not for the very clear text regarding Durin's Bane, it wouldn't even be a question resurfacing every 10 weeks or so... no other text would even raise it to speculate about.
Added note: p.s. - other than the above, Ent has no opinion on the matter whatsoever. 😁