Yes, as in the same way, when a dot is put after a minim becomes a dotted minim, a dot after a minim rest makes it a dotted minim rest.
Its an abbreviation for Marcato, which means that the music should be emphatic or accented.
generally the bass instrument, I play the baritone saxophone and it stays at the same beat mostly with the bass clarinet.
I can't think of any commonly used musical terms beginning with Y, although I can just about convince myself that I once say "Yearningly" in a piece. I may be making that up, though.
One phrase that's heard frequently in jazz circles but won't appear in an arrangement is "Yeah, man."
Adagio means "to play slowly". This tempo marking is slower than andante, but a bit faster than largo.