I cant speak directly to your fediment concerns because I'm simply not knowledgeable enough, but its a good question.

However, I would like to point out, that if we zoom way out, its clear that some type of federation is the only real solution for mass use. I mean imagine tomorrow 1B people decide that they want to use Bitcoin....how would those people even onboard? Even if LN is ultimately a solution, how do they even get into LN?

The most probable scenario would be that they onboard via some type of exchange that then gets them into fedimint / LN / whatever. My point here is: true wholesale scaling will require some type of federated approach at best - or a single custodian solution at worst (Coinbase). So given that choice, we should aim towards federated solutions....of which fediment and Liquid are both contenders.

As an aside, I know that Liquid is talking about launching their own LN solution, which to be honest could wind up being a "good enough" solution for 99% of the "onboard - scale" issues of mass adoption.