This may be out there, but I was kinda under the impression that Trump himself was doing it to impress Putin. Putin really wanted someone with his interests in mind after the magnitskty act. Most of what you posted may have been from optimistic associates who weren't fully grasping the situation (like Padadopoulos for example).

So Trump, and Manafort, both with dubious relations to Russia, were effectively gonna try their damndest for their own best interest and to appease the Russians but I don't think they actually expected to win. Remember Trump was calling it rigged before he won. There's also that video of him looking unhappy when he first realized he won, I can't find it right now.