Yeah, exactly. For those who didn't catch it: linked lists already have O(log n) overhead, because distinguishing between n items requires log n bits for the pointer. They're fundamentally not in-place.
For sure, if it doesn't make sense to use a linked list in the first place then linked list merge sort definitely doesn't make sense...
Absolutely. I'm not even sure how you would do such a thing.
I personally have found it interesting when considering the difference between an array of pointers and a linked list, simply because they both have the same overhead but one doesn't require allocating any more memory for a merge sort.
I basically agree with what you say (maybe bar it not being useful knowledge) but I don't think it's worth continuing trying to clarify my initial statement.