1. Yes and yes. Though Gorgon is technically Titan. Pure Monsters (such as Wyrm or Manticore) simply have no body slots for armor or hands slots for weapons. However, you can still make for them miscellaneous items. These include both armors (Bracers of Defense, Amulet of Luck) and weapons (Dancing Trident, Stone Bird). And while some Pretenders can function well enough without such, later in the game it will become necessary. Especially if they don't have natural regeneration!
2. Armor for magicians is more complicated. It provides protection, but also makes them fatigue faster. And unconscious magician isn't something you want! Furthermore, fatigued units tend to suffer critical hits more often - and this cripples them even if they survive. On the other hand, a magician killed by a stray arrow isn't something you want either. So it's better to look up for armors with lower encumbrance for you magicians - such as, i.e. Lightweight/Weightless Scale Mail, Shroud of the Battle Saint, Weightless Tower/Kite Shield, Talisman of Missile Protection. One of the best armors for magician from my point of view is Rainbow Armor - not only it light and gives protection, it also actually cures your fatigue and provides a Magic Resistance bonus on top of that!
If you want somebody who can "really tear things up", however, you should think about whole pack of items and here you can include more heavy armor or one with additional effects, such as Rime Hauberk/Bone Armor, Charcoal Shield/Vine Shield, etc.
And forget about D&D - there are many better games!
