If Democrats gain a trifecta, will they actually abolish the filibuster and pack the Supreme Court?

[Vosem]

It seems like concern about abolishing the filibuster is fairly widespread among the Democratic Senate caucus; the current leader was on record opposing filibuster reform during their previous majority period and you have plenty of old institutionalists and swing-state Senators (using an expansive definition of swing-state -- extending to people in obviously Leans-D states) who oppose it.

Current polling suggests a 51-49 Democratic majority (with a loss in AL and gains, in order of likelihood, in CO/AZ/ME/NC/IA), which I think is very unlikely to result in filibuster abolition, except for maybe extremely specialized votes which don't recur often (like admitting new states). Something in the mid-50s might be likelier to abolish the filibuster.

I think Democrats will find actually passing HR 1 in any recognizable form rather harder than the GOP found abolishing Obamacare to be.