[Mobhack]

Weapon 1 is only multiplied by number of men if it is a CLASS 1 (infantry prime) weapon, as explained in the mobhack help. In other words, rifles and SMGs and not LMGs.

An LMG unit with the weapon in slot 1 and rifles in other slots has the rifle as a secondary weapon, therefore.

As to the little light mortars - they are direct fire weapons, unless you buy the version of the German OOB where the 50mm tiddly mortars are implemented as a light mortar class in one formation. ~500m ranged indirect fire weapons are just about useless - but apparently some folk love the things that way. I prefer the heavy infantry section type, and firing direct over open sights than waiting 2-3 turns for fire to arrive (by which time the fight has likely moved elsewhere).