Republicans are still somewhat divided as a party. There is a real possibility that every now and again they'll cross the aisle and side with Democrats to keep a lid on things. What's the rule on filibusters?
Will be interesting to see if Democrats reciprocate in weaponizing the filibuster. They've spent the last several years complaining about GOP doing it. Now is when we find out to what extent they're willing to replicate that model for the sake of protecting Obama's legacy. Of course GOP could change the rule (the so-called "nuclear option") or they could repeal the ACA with a budgetary vote, which only needs 51 votes; legislation passed by that method sunsets after 10 years, however (as with Bush tax cuts).
They will immediately begin filibustering. But it's a stopgap solution. Generally speaking I think it will work occasionally, enough that Trump's list is foreshortened but not defeated. From a practical standpoint, a lot will depend on which of his policies go through and which are stonewalled, because I like some and dislike others, but I can't count on anyone in Congress from either party to agree with my specific perspective.
Will be most interesting to see their position vis Supreme Court. Considering McCain's position that Clinton not be allowed to nominate a justice at all, Chuck Shumer might as well come out and say that we need to wait for the next president so that the people can have a say in the Court. It's an absurdist position, but not any more so than McConnell's. I'm not in favor of the government grinding to a halt, but I also don't expect for there to be no reciprocity from Shumer, given McConnell's behavior since 2010.
Justice nomination has always been a glaring problem in our system. There isn't a particularly fair way to do it, especially now that justices are contemplating early retirement in order to secure a like-minded successor. I don't know if anyone has put forward broad solutions to the perverse incentives we have now.