Are there any sidechain ideas or proposals that depend on the ability to create non-malleable transactions?
Nope. Malleability isn't an issue for well confirmed transactions, which is all that any sidechains proposals work with-- often 100 blocks or more. But that hasn't stopped people you associate with from dishonestly claiming that segwit exists to enable sidechains. I doubt having this further confirmed will suddenly spur you on to calling out their incorrect claims, since you don't for anything else.
That is also what I thought. I am sorry if I am not calling people out. That is not my purpose.
I asked this because I was curious whether any connection between the two was defensible because that seemed unlikely to me.
I am not going to "call people out" and I do not understand why you expect me to or why you seem to have problems with me not doing so.