A person can only get one "Guarantee" per stay. And actually, the FFI one wouldn't apply as I do believe for it to apply the reservation has to have been made at least a day or 2 in advance. Since the FFI didn't get a "reservation" for you until the last minute, they aren't on the hook for anything, but the CY is definitely on the hook for the Walk Guarantee (assuming your MR# was in the reservation of course).

Did the CY pay for your first night at the FFI? They should have. And you should also get the $100 as well. Note that even if your MR# wasn't in the reservation I do believe the hotel still has to pay for your first night at an other hotel if they walk you (as that is not an elite benefit but a general walk benefit for everyone.)