There shouldn't be a single Democratic vote for a bill like that. Pathway to citizenship or nothing. Frankly, we should just wait until we have a Democratic president to do anything of this magnitude.
Following the Republican obstructionist playbook they pioneered (along with the same breathtaking chutzpah), we should demand concession after concession, and then vote against the final bill anyway, forcing Trump to pass it on Republican votes alone, and then accuse him and them of excessive partisanship.
Same should apply to any and all bills they attempt to pass.
The filibuster for legislation will always be a thing. If there are no Democratic votes, then nothing gets passed.
Are you sure about that? Bear in mind Mitch McConnell always has the nuclear option. And I don't doubt that Trump would strongly encourage him to use it, whatever the long term consequences may be.
I doubt there are 50 republican senators that are stupid enough to do something that would, a few short years later, give the democrats unilateral power to abolish the hyde amendment, ban assault weapons, raise income taxes to 50% on the wealthy, etc. Cabinet nominees are only in power a few years, judges have to receive actual cases and can drop dead at any random moment, but laws always enact immediate, lasting change, that quickly garners a devoted base of supporters that make any repeal difficult. Thus repealing the filibuster for legislation is honestly nonsensical - it's getting a border wall (MAYBE) while losing on literally everything else. Republicans aren't THAT dumb.