Stalinism and Maoism aren't going to work, both in the sense that the conditions those ideologies were based around aren't really present in the US and in the sense that there is too much bad blood in the sphere of public relations thanks to the spectres of the Cold War.
Leninism MAY be viable at least as far as strategy goes (though many might argue that the Vanguard Party is something of a historical artifact given the changes in material conditions that have come about in the later 20th and 21st century). However, pretty much any actual reference to Lenin would need to be stripped and the ideology would have to undergo massive re-branding if it doesn't want to fall prey to the same problems as ML/Maoism.
Trotskyism would likely amount to what it is now, which is to say a platform for social democracy. Otherwise it will fall to the same problems as all the other branches of Leninism if it actually tries to pursue a revolutionary program.
Bordigism's connections to Leninism are just obscure enough that most Americans probably wouldn't make the connection, but most would likely reject it due to its focus on centralism and rejection of democratic methods.
As far as I am aware, Situationism really doesn't have any concise political programs/policy tied to it, so who knows where that could even be taken. It would likely have some decent appeal as a form of critique however if we were to see a larger rejection of consumer capitalism and mass media manipulation.
Luxemburgism or other ideas cut from the same cloth are probably the only bet explicitly Marxist ideologies have of penetrating the American political consciousness.
Ancom appeals to many of the sensibilities that the American public holds to be of importance, but the terminology would again need to be re-branded so as to help sever it from the muddied historical legacy of the Cold War while still retaining the central principles of the ideology. Communalism is, for all intents and purposes, an example of such re-branding.
Anarcho-collectivism would be in a similar situation as ancom, but with the slight advantage that it doesn't have to bother with obtuse discussions of how "X person deserves a greater wage than Y" despite the fact that one of the central tenants of ancom is the wholesale abolition of wages as a functional concept. Ancol or ancom would probably be best implemented through some variation of syndicalism considering both its historical presence in the US and use of unions as an alternative to other organizational tactics that have thus far had considerably less success in mobilizing workers towards collective action.
All in all, as OP and many other have said, Mutualism is probably the best bet, which is unfortunate considering it sees the least amount of change from modern capitalism when compared to many of the other ideologies listed.
