onyx bolt extra damage is classified as ranged damage, but so is dragon e bolts extra dmg (you just hit 0 if dragonfire protection), so both damage instances should be reduced by prayer protection (reduced by 40%) unless this is calculated after the actual hit and this after the prayer protection is applied, but i don't know this.
Claws spec is 115% of normal hit strength, and 120% of normal hit accuracy
Normal: First hit is anything of the full 115% normal hit, second is half dmg, third and forth are a quarter.
If the first hit hits zero, the second hit has a chance to hit full 115%. If this happens, then the third and fourth hit will be half of 115% instead of a quarter
if the first hit does not hit zero, it will continue as normal
if the first hit is an odd number then the third and fourth hit will have +1 hit (essentially a 50% chance)
Multihit for spells are all randomly calculated (essentially a random number between 0 and max hit, just like every regular hit)
The untradable kit item will drop as itself, it does not show up for others