Regarding what was established, we never really learned that the grey individual from "Conspiracy" would have been a Bolian.
That was the intent. The name Bolian is derived from Cliff Bole, director of the episode which introduced the species. Bole directed Conspiracy, not Allegiance.
Or that the Bolians would be UFP members of any sort, least of all founders. To the contrary, the first-ever appearance and mention of a Bolian (albeit a fake one) in "Allegiance" indicated that Bolians pursued an independent foreign policy, wrt the Moropa.
Granted, Andorians and Tellarites were also "maintaining an uneasy truce" with each other once, sort of - but that was semi-friendly banter between UFP members. The Moropa did not appear to be UFP members any more than the Bolians did.
Although it is true that a deleted scene from a TNG episode indicated Bolians were not membes of the Federation, later episodes seem to imply they are. DS9 even featured a Federation ambassador
who was a Bolian.