As an instructor MBCT, I can tell that as far as I know models for meditation do not exist at the moment because a potential model should include BODY and MIND...

I don't believe that MBSR and MBCT rely on the cognitive model, in that there is no underlying assumption that changing cognitions is necessary for change. Both are more experiential, relying on the client's curiosity and openness to come to their own insight about their relationships with their internal states. MBCT was designed as a relapse-prevention extension of CBT, but largely focuses on decentering the client from their thoughts, as opposed to actively changing them. So I wouldn't say that it's intentionally functional contextualist, but more so is an exploration of what works given research on the differential activation hypothesis and theories for why rumination and relapse occur in depression.