They can use zon bows in D2R
And yes, they do get the bonus from the +skills
A1 merc dmg is kinda irrelevant, she’s there for 3 things :
Give fana to the player
Cast inner sight
Possibly knockback enemies for defensive purposes
The ideal setup to achieve all 3 :
Faith Matri
Gskull 2 x 15ias (reaching max ias and giving her KB and CB)
Coh (leech and tankyness to help her survive)
If you don’t want her to KB, replace Gskull with FF or Cure
GMB is fine, similar dmg even if she loose 1fpa compared to matri, due to higher base dmg.
But again, her dmg is pretty irrelevant… less attacks/s means she will cast inner sight less often and apply KB/CB less often
No big deal tbh