Frostbolt + Cast on Freeze Cold Snap and some mana recovery concerns

I have a Cast on Freeze + Cold Snap setup, simple idea, after your enemy is frozen it should instantly consume the freeze on that enemy (one freeze is enough to charge Cold Snap). Sometimes it works how i expect it to work, sometimes it doesn't. I have two things regarding Cold Snap to complain about.

1) (Ice Nova + CoF setup) Intuitively, for every frozen target there should be one Cold Snap, yet sometimes it feels like i don't proc enough Cold Snaps, since i often see monsters that are still frozen. If you think about it, something like that shouldn't happen UNLESS you freeze multiple targets at the same time, which shouldn't happen often since Ice Nova expands gradually from your character. It would be really nice to polish the interaction and achieve the desired 1 freeze = 1 Cold Snap outcome. In a perfect world nothing ever remains frozen with CoF + Cold snap setup, even if you somehow freeze multiple targets at the same time.

2) (Frostbolt + CoF setup) Cold Snap proc detonates Frostbolt instead of the frozen target. It would be nice to change the priorities of Cold Snap and stop it from casting on Frostbolt entirely when socketed in a Cast on Freeze, i doubt people would ever WANT it to target Frostbolt. One way or another, Cold Snap detonating the Frostbolt instead of a frozen target must stop, its a huge damage loss.

Regarding mana recovery, i will provide a scenario. Arcane Blossom notable provides 15% increased mana recovery rate. I had no other sources of mana recovery rate, only sources of more and increased mana regeneration rate. Having 74 mana regeneration, i expected to gain 74 x 0.15 = 11.1 mana regeneration, yet it only gave me 4 mana regeneration. In classic PoE fashion, i believe different wording means it should stack multiplicatively with sources such as "more" and "increased", but it doesn't.