So some talents like Soul Conduit and Rain of Chaos, gives you a 15% chance to refund sould shards or summon an infernal, based on every soul shard spent. I’m curious if the 2 piece bonus counts towards those % bonuses? Since you get a “free cast” of your chaos bolt, does that free cast give you 30% to refund soul shards, or summon an infernal?
It’s complicated, as a rule the answer is a NO; but there have been cases where they open exceptions [ Demonology Demonic Calling makes Call Dreadstalker cost 0 soulshards, but even then Call Dreadstalkers have 15% chance to refund 1 soulshard per soulshard spent as if the spell costed 2 soulshards]
As far as its been looked in the past on 9.2; the answer is: No for the Free Chaos Bolt from  of Destro to Proc Rain of Chaos or Soul Conduit.