You cannot be a Dharma practitioner and yet reject rebirth. Do we really have to have this conversation yet again?
I doubt that someone like Trungpa rejected rebirth in his own practice, yet he did not make a huge issue out it with his students. If so, then how he chose to guide his students towards Dharma is limited only by his own realization and upaya/skill. Thus there is room for acceptance or rejection of what he did, but based only on how one sees his attainments, not on how much latitude a realized teacher has on guiding their students towards Dharma.
For me, he was not my teacher, so I feel no need to formulate an opinion about whether he was realized enough to use his discretion to adapt things the way he did. But I acknowledge that there is room for that type of thing within the tradition--if needed and by a fully realized teacher.
You do realize that he participated in Dagara initiations with an African teacher named Malidoma Patrice Somé?
He is very open minded, maybe too much so. He has not limited his open-mindedness to the teachings coming from Tibet. That may or may not be a good thing. Personally I leave my comfort Zone at the edges of the Vajrayana.