Fighting Stance, Armsman, Critical Charge, Savage Strike, Paralyzing Strike - All apply to dual wield as well right, or at least give the bonus to both individual weapons?
Right. Each weapon is one-handed, so each gets affected by one-handed perks.
Bladesman - I'm pretty sure they do, but just to be safe, do Daggers get this bonus as well?
I haven't taken that perk myself, so I can't say with certainty whether daggers get crits, but notice that the perk description says it gives a crit chance with
swords. A dagger is not a sword, so I would not expect daggers to be affected.
Given that I get a notification in the top left of my screen when my bow gets crits, I would expect that sword crits are also displayed there, in which case it would be easy to determine whether daggers also get crits from Bladesman: Take the perk, go through a few fights, and pay attention for crit notifications.