Damage conversion questions

Simple question,

Ground Slam is physical damage
Added fire damage converts % of it to fire damage
Does avatar of fire convert it to 100% fire damage like infernal blow does + Avatar of Fire?
Does it benefit more picking fire nodes or physical nodes?

thank you :)

Just realised that Added fire damage doesnt convert, but it only adds =/

But will ground slam with added fire damage benefit from AoF or is it just not a very good idea to do so?