Just came from a siyum. I’m wondering if it is preferable to fast or to have a siyum?
As far as the OT, perhaps the b’chorim will do the Avodah while the Kohanim, who are also Levyim obviously, will play the instruments and do what the Levyim do (along with the ‘plain’ Levyim.)
Another interesting issue is whether a Ger may be considered a b’chor, since a convert is considered to be ‘born again’ at the time of conversion. Probably not though since he is lacking peter rechem.