Long answer because I did put some thought into this once and that's a fun question:
Before I started making games on a regular basis, I did have the idea of all of them taking place in the same universe at least, although some in vastly different points in time. So that would be a world filled with mysterious artifacts, ancient buildings, and the occasional curse.
I'm not sure if one could still argue that makes sense, but Duality of Opposites could be like an arcade game that exists in that world for example, and then Warper might take place in a distant future. I haven't really done anything concrete with that idea though (yet?).
In other words: I wouldn't say there really is an "official" canon right now, so I'd like to think your take is as correct as mine.
That said, this might change, but currently my idea was that the Cursed Travels protagonists and the Temple/Tower guy know each other. I'm thinking the Soul Mirror person is active in their world as well, same for the Firefly Forest character. Things are still moving around in the Amidst the Sky sequel's story, so uhh let's leave it at that.