Do you have the application or approval emails? IIRC there was a reference number included in one or both of those that's used in the "setup your account" email link so you can do it before you get the card.
I don't believe you have to pay to transfer now, so it's worth a call. FWIW, I had hubby call to transfer points from my account while we did a reservation and they transferred the points with no mention of the fee. Hubby is Plat, I'm Silver. So under the previous terms I'd have paid $10 per transfer since technically the member sending the points is supposed to call. But I figure worse case is you have to get DH to give verbal approval on the call and you having the Gold status might get around that since it was waived for Gold and Plat members, if they are still charging for transfers.
Trying to have multiple members on the reservation and getting it credited to the correct account seems very hit or miss now. I saw one report on r/churning after the merger that it worked out for someone. Someone in their party did a points+cash booking, then at check-in he added his number to the reservation to give status to the room and he got the elite night credit afterwards. So it seems like it can happen, but I have no idea what stars have to align for it to work. For me the first try was a straight points booking, second was a FNC; no joy for either. In theory a points+cash booking should look the same to the hotel because you're just buying points and the hotel still gets a e-cert, so not sure if that's a factor on why it worked for them or just luck of the draw