Apparently, the mercenaries get huge bonuses (2x for rogue, 3x for barb) from the sorceresses ENCHANT spell due to how their damage is calculated.

Rogues get 2x fire damage due to the bonus being added to both their base amage and weapon damage.
Barb mercs get 3x frome base/1 hand dmg./2hand dmg.

No one was certain how Act 2 Spear Mercs were totaled. One suggestion was base/throw/melee.

Also if a barb merc is equiped with a 1 handed sword, does the barb get base/one hand/one hand, or just base/one hand?

MORE on mercs.

What exact types of weapons can all the mercs use? I tried to use a unique MF crossbow formy rogue merc but couldn't. Do amazon bows work for rogues? Also can Sorc mercs use sorceress orbs? Daggers (specifically gull), 1h clubs, 1h axes?, or just "sword" class weapons?

I know barbs can use barb specific helms, but do they benefit from + to BASH bonuses? (or whatever other attacs they use)
Do act 2 mercs benefit from + to paladin skill items, or amazon + to JAB items? How about Spear/polearm masteries.

Spearman
Spear/Polearm/Javelin, Armour, Helmet
+ Skills to Paladin works on their Aura, + Skills to Amazon works on their Jab

Iron Wolf
1H Sword, Shield, Armour, Helmet
+ Skills to Sorceress works on them

Barbarian
1H Sword, 2H Sword, Armour, Helmet, Barbarian Helmet
+ Skills to Barbarian works on them

Also, any bonus to a specific skill that a merc uses works on that mercenary, for instance Bash will work on a Barbarian, but Iron Skin will not.

If you mod a 1h_weapon's 2h_dmg from 0~0 to 50~50 in weapon.txt,
the barb,ironwolf or desertwarrior(1h_jav)will display more damage.

But all above are only display which often cheat us.My barb pet
uses a ONE_HAND_SWORD with 1h_dmg=1~1,2h_dmg=80~80 and he can
hardly kill anything.He still uses "base_dmg + 1h_dmg" to fight
because a one_hand_weapon is equiped.If it is a two_hand_sword
with the same damage,the monster loses its life quickly.

IMHO,the X2 and X3 are just phony.