Hi and welcome to BW!
. Congratulations on your twins!
I think if you've been doing the DF for a week and not seen any improvement in their NW, you don't have to keep it. It doesn't work for all babies. I do wonder though, if you could get them to take more at that feed if it would make a difference. 2-3oz doesn't seem like much for 9 week old babies.
I've never been a FF, so am not sure on this, but they do seem a bit young to be on 4hrly feeds. I guess as long as they are getting the oz they need, it's probably not an issue, but typically LOs don't move to a 4hr EASY til around 4mo. I don't know that this has anything to do with the NWs, but is just something that stuck out to me.
As for getting Tate to not wake, since you've ruled out hunger, I think you'll have to work on resettling him without bringing him into your bed (which I don't blame you for at all!). We don't condone any type of CIO at BW for babies of any age, as it can lead to undue stress on your baby and isn't often a permanent solution. Have you tried shh/patting (or some other similar method) him back to sleep? Do you think he is waking out of any discomfort from the 12/2 feed? Trapped gas or something similar?