I would be surprised if they were not involved in discussions. They may not have full voting power until joining officially, but I'm sure their input is being allowed.
In the end, though, I think they are going to be about like any other member. They will want the easiest schedule possible, so long as they keep their rivalry games. And for OU and Texas, all that really matters to them is their game against each other. If it is the 3 permanent opponents model, they'll probably give Oklahoma the trio of Texas, Missouri, and either Texas A&M or Arkansas. Texas will likely get Oklahoma, Arkansas, and probably someone like Ole Miss.
Texas A&M has been adamant that they do not want to play Texas because they are truly the whiniest, most pathetic program in the conference. Oh I forgot the blue font. But not really. And it seems the SEC is willing to grant their pitiful request, so that game is likely not going to be an annual contest.