yes

forgivable = yes. forgettable = not necessarily.

i would say that not all transgressions are forgiveable

like what transgressions? there is one unforgivable sin that I know of, but that's not a transgression.

that would be blasphemy against the Holy Spirit. [if I recall correctly]

a transgression is a 'sin' that you do, ask forgiveness and then do it again anyway.

am I off track, or is this inline as to what you're asking

I think what is meant by a transgression is behavior that flies against the expectations of a relationship.

depends on who's doing the forgiving, I suppose

if it was a blatant "choosing her over you" transgression, then no. if it was a misunderstanding, then maybe.