I don't know the answers to your questions as I have never tried this and never would.

But if I were you, instead of being worried that one of the stays may not be qualifying or points may not post, I would be worried about my account being frozen and all points forfeited as result of an audit.

This is an obvious violation of the program as you as a member cannot stay in two hotels in two different countries at the same time and although the quality of the IHG IT systems is often questioned I would expect that such an easy check will be part of the audits that are performed every once in a while. Accounts have been frozen and points forfeited in the past for less obvious cases of "suspected fraud or abuse".