Rakuyo wrote:You conclude that Aldrich ate Smough, and therefore releases his armor upon death.
I think the connection is simply that they're both depraved maneaters, and both linked to Anor Londo.
A lot of possibilities exist, and it could even be that Aldrich is an evolved form of the surviving Smough.
I actually wondered if Aldrich was a Smough variant, but I can't find any support other than eating people. In fact, they actually have contradictory paths. Aldrich with the church and Smough still being tied to Anor Londo as a ”Knight.” I'm not saying it's impossible, but that'd be a lot to reconcile.
Primarily there'd be a matter of conflicting timelines if that's the case. DS3 gives a decent view of Aldrich's events which culminate in Anor Londo, but are a pretty well established path starting elsewhere. Smough on the other hand, according to DS3 anyway, never left Anor Londo.
So then, there is a good deal of evidence to think they're separate. And to put the pieces together again, Aldrich's path ended in Anor Londo in the area we're used to seeing Smough in. DS3 lore says he stayed there the whole time. Yet we never see him there.
In other words, he's supposed to be there but there's no trace. In the place you'd expect him (according to the items anyway) is an entity that is on a warpath to eat Gods. One in which he's started to become successful as he clearly has Gwyndolin.
TL;DR: If we take items even a little on faith, Smough not being present is contrary to what's stated, which is a path that's established to be quite different than Aldrich's. While there could be an intended parallel to explain the presence of Smough's armor after beating Aldrich, that doesn't adequately explain the elephant in the room. DS3 says Smough never left the Cathedral. So, the simplest solution I feel is what I presented. He remained faithful to his post, and we know for a fact his post came under assault from one of the more powerful entities around.