Let's try to match them up. For some of them, their characterisation is so extreme that it's pretty clear they represent a sin that RJ presumably considered unforgivable in some sense. For others it's not so obvious. This is what I have so far.

Aginor: Disregard for nature or the natural order.
Asmodean: Pride?
Balthamel: Lechery, sexual abuse and wrath.
Be'lal: Envy.
Demandred: Excessive ambition and competitiveness, lust.
Ishamael: Hard to say. Hopelessness?
Graendal: Vanity, narcissism.
Lanfear: Jealousy, lust.
Mesaana: Brainwashing.
Moghedien: Cowardice.
Rahvin: Envy or lust? Not sure.
Sammael: Treason and pride.
Semirhage: Sadism.

Pride, lust and envy are sort of catch-alls that fit on many of them.

Also not sure where Taim comes in, if anywhere. Maybe also brainwashing.