If McConnell really wanted Trump to win, he would have promised to keep the seat open until 1/20/21 and I honestly think that would have been the end of the Biden candidacy. Every single one of the Republican voters for Biden would have come home immediately and it would have been over. But he's not going to do that because there's still a pretty big chance Trump will lose, so he's taking the safe route of ramming through a vote right now.
Except the “Biden Republicans” are pretty moderate overall. They are likely heavily pro-choice and not fans of ACA repeal.
Yep. Also, Biden could probably win even without Biden Republicans (although they certainly help). The Supreme Court helps more with turnout among party bases than anything else. And the death of Ginsburg doesn't change the reality that the President has the power to appoint justices; it just brings it to the front of everyone's mind.