Anyone know if spirit wolves cold damage receives dmg buff from things like HoW or Might aura?
It doesnt, its cold damage.
Sadly 2/4 summons dont get dmg bufs from auras or wolverine spirit.
Ravens are ok cause they do high dmg without any bufs but spirit wolves would be nice to get a buff cause 500 dmg with 31 lvl is a bit low, isnt it?
It was suggested they treated SW like Amazon cold/fire arrows that did a phys to cold/fire conversion, so they benefited from HotW and other auras.
But no luck.
With things like Dark Shapes having 100% resist physical and 80% resist cold and 5000 life, its hard to see how a pure summoning druid can get past these things.
A3 fire merc would be awesome, but neither mastery nor synergy leaves enchant damage at ~2xx 
Poison Creeper might be the only effective non-phys damage available.
For ladder start, just make a Lawbringer and slap it on an Act 5 merc until you get your hands on a Reaper’s Toll for an act 2 merc.
Was thinking to do that on the dual act5 barb but dunno what to give him as a second weapon. Budget gear atm on single player
Crescent Moon or Oath are good budget options. Or just grab something with Crushing Blow.