Thanks, all, for the responses--which as I suspected were varied. I definitely will not be doing anything illegal with the receipt.

We decided to go with the first option, which is entirely in keeping with the rules, and will make sure to request in enough time that the final bill is in my name and of course charged to my card. It's less important where the points go, especially since "my" card is that of an additional cardholder on my partner's Bonvoy Brilliant Amex--so the spend multiplier will reach us either way. My partner had been on a Titanium quest this year, but doesn't look like he'll make it anyway, without or without the nights from this stay. Ultimately, we'd just like whatever platinum benefits are available.

Thanks for the reminder not to get the prepaid rate! It's only like 5 euros or so a night difference, and obviously worth it to make sure I get the whole week reimbursed. As a wise person above noted, free lounge access is not worth it if the lodging doesn't get reimbursed!