All classes, even wiz´s, can use BMU, as it is considered a suit, rather than heavy metal armor.
no they can't, my soloing monk couldn't use it and neither could my wizards, cheat yourself to it and experiment.
edit: maybe on a mod they can but in the real BG2 they can't.
Also, swashies cannot use whirlwind, can they?
yes they can, only it's like greater whirlwind actually 10 attacks per round not 6.
Well, with about the 100% magic res, the only thing I should worry about would be imprisonment.
the simulation is ordered to charge back and attack, meanwhile the swashbuckler finish's his spell of abosolute immunity (makes you immune to all physical attacks not magical, but monks can't cast spells). Swashbuckler then lets loose chain contingency which makes 3 pierce shields hit the monk which lowers his magic resistance down to 0 (since you can't get into negatives).
Remember, being Evil in Baldur's Gate 2 is VERY fun...