Today federalism connotes an emphasis on limiting the powers of the federal government in favor of state and individual rights. Thus, the Federalist Society is a libertarian leaning political and legal membership association that promotes less regulation, and in particular emphasizes a diminishment of federal regulatory powers.
So federalist would, I think, be appropriate today. The Federalist Society is hardly non-partisan, but the terms federalist and federalism haven't [yet] become associated with any partisan political ideology. And the Federalist Society is still quite respectable, IMO. They largely maintain an earnest and honest legal and scholarly discourse, unlike many other right- and left-leaning political associations today.
> the Federalist Society is a libertarian leaning ...
The Federalist Society is establishment, movement arch-conservative. They are the legal wing of the elite, establishment conservative movement, with several Supreme Court Justices as members. If you look at the list of members here, you will see it is not libertarian or libertarian-leaning:
The federalist society and their website's published opinions look to be to be doctrainaire right wing conservatives. If you look at the about us entry of their webpage, it says individual liberty and traditional values and the rule of law.
I might say "federalist", but AFAIK in the US that's pretty much reserved for the effort to make the Constitution back then.