Q: Can Logan Lashley use his Hero Ability if the attack he performs is a miss?
A: Yes.
Source: Official Errata
Q: When he performs an attack, does the Stalker gain the +1 h from 'Set Trap' for each trap token he is adjacent to?
A: No. If the Stalker is adjacent to multiple trap tokens, he gains only +1 h on each attack.
Source: Official Errata