Co-promotion would only be for his boxing promotion and perhaps some of his product lines.
I seriously doubt the UFC will make him a partner. How much he can get out of a co-promotion deal is anyone's guess, but I would bet it would be contingent on him fighting, i.e. he gets co-promoted when and if he fights only, in the cards he competes in. Not a permanent deal which would lock the UFC up with him regardless, which would be ludicrous and of course won't happen.
I agree that those things are part of the current negotiation. But I honestly think his current peak value hinges primarily on his championship, and that if he loses his stock will suffer considerably. Of course, if he loses to Ferguson, say, he could drop back to FW and challenge for the belt, or fight Diaz and call it a day if he loses that.
There's still many fights from him. But he is one loss away from losing his present bargaining power, and two from really receding into a much lower level.
Mind you, this is all thinking of his drawing power as a fighter. I don't know how his other businesses are doing. But of course sponsorships, media coverage and advertising would all take a hit if he loses, so...