You are correct about the group and litigation, though Siegel was a member of The Tokens at the time of the 1988 release (see Wikipedia for more on the lawsuit). I'm not sure what the outcome is/was since one of the people involved in the suit died in 2017. Siegel was a member of The Tokens at the time of the 1988 recording.
a) Yeah, I had read that Wiki portion and offered as part of a related error report. If the litigation is on-going, I suppose the deceased estate would take over as a party.
b) I'm not sure who or what source to trust on membership. Was Siegel of member of his "Tokens" or the "official Tokens"? It would appear his "Tokens" give how the reissues were re-credited, notwithstanding how releases are entered on Discogs, etc.
Frankly, given recent SHS experiences, I'll likely just decide how to handle for my notes, not worrying about any possible errors on SHS.