This page gives specific rulings about card conflicts.
Some fighter can use multiple one-handed weapons at once. If the fighter receives a max damage bonus for a particular item as a fighter ability (not from a weapon, item, or other card's ability), then the fighter can attack with multiples of the certain weapons in the same turn. However, all max damage bonuses are lost for each of those weapons during the attacks. Attacks may be declared against seperate opponents, but must be declared at one time.
A Draconian S.L.E. gets +1 to sonic pistols. If the S.L.E. equips two sonic pistols, he or she may attack with both in one turn, but without the +1 bonus to either pistol. Each pistol could be used to attack seperate fighters, or both against the same fighter.