I don't know if there is any performance difference between .Start = .End or .Collapse wdCollaspeEnd or not. If there is I wouldn't think it would matter a nit.
Not a nit, as they are numerically - and ranges are just numbers - identical. There is no change to the memory allocation. That is the advantage of ranges over Selection; a range of 1,000 characters (.Start = .End -1,000) uses exactly the same memory as a range of 5 characters (.Start = .End -5). Unlike Selections of the same number of characters, as Selection uses GUI memory allocations.
I rarely use integers and use longs
We should, as a best practise, only use Long as Integers are no longer used at all by VBA. You can declare them, but the parser converts them to Long on its initial parse pass. While I suppose you could say that the conversion itself takes time, and is true that the memory blocks (being larger for Long) need destroying and reallocation (and thus you really should never use integers), but I suspect that you would have to declare thousands and thousands of integers before you would be able to even detect anything. So yes you CAN declare integers, but why not just use what VBA uses...Longs.