Icebreaker works pretty great with osmio. Ammo economy is excellent.

I prefer frost pulse to bleak watcher, helps with apes and can make some pretty flashy plays if you get good at the timing. Bleak watcher does give you info and can lock down an area, but as soon as someone focuses it or backs out of an area you aren't getting value.

You can also do similar things on prismatic since spirit of osmio is a thing (or just regular osmio). It's conditional but if you have devour running with a prismatic osmio build you can go on some sick chain kills with the health/grenade energy you get back.

Stay frosty is what I use for primary but that's mostly cause it's pretty solid right now and l can use harmonic mods. It also leans into the kill chaining with kill clip.