I can only offer my view on Diamond amenity.
Unless your wife is "checking in" on Day 2, you can not earn diamond amenity more than once.
If she does, then you will be earn the Diamond amenity for days 1 and 3.
As for rooms, I am not sure how things will work out.
If you are upgraded on Day 1 you may keep the room if front desk can reshuffle things a bit.
However, since you need 2 queens on day 2, keeping the same room does not seem to be an option.
RM