Got questions about skill procs/viability for two builds

The builds in question are a Vaal Pact build and my Freezebreaker build. The interaction i am questioning is Cast On Melee Kill. Ill explain my builds and then ask the question relating to the build's possible interaction with the support gem in question.

Freezebreaker build: This build is a facebreaker build that utilizes the Shadow rather than the Marauder or Duelist. Basically its based on physical damage and cold damage.The skills utilized are : Hatred,HoI,Infernal Blow, Frenzy, And Frostbite.

I use Frenzy to proc(with curse on hit) Frostbite on tougher enemies and Infernal Blow with HoI for constant aoe clear. HoI seems to work perfectly with Infernal Blow's explosion. Anything that doesn't die is immediately frozen because HoI is connected to Elemental Proliferation so it spreads the frozen status. Works very well so far as planned.

Now the the reason for the question. Because i have to invest in intelligence to get my cold/freeze nodes, i have more than enough int to easily use high int req gems so pretty much all cold spells are easily available to me. However i don't want to really stop to utilize my spells, i want to keep focusing on attacking quickly to keep my charges and keep infernal blow freezing. So i need to be able to proc my spell instead.

So that leads to the question: How would Cast On Melee Kill Work with Infernal Blow and can it work? If i could i would like to make it so that killing in melee would allow me to fire off a multi arctic breath. But can i even do that with infernal blow? Does the explosion ability it has cancel it out and make it so it won't work or will it work despite it?

Vaal Pact/Blood Magic Build : This build is a Reave/Cyclone build that uses the Haste aura/Vaal Haste. I have high life on hit and leech, plus plenty of attack speed. Reave also uses multistrike.I also use spell totem for constant Warlord's Mark cast without me having to manually cast so i can focus on attacking.

The question here is a rather simple one: Since my int isn't all that great, what would be the best option for Cast On Melee Kill for him? I would link it to my Reave or my Vaal Reave.


Thank you in advance for any help.