1) 24 or 30 - depends how much do you want to depend on casting and how much on melee part
2) 40Int/40Faith is totally ok, but you can do with 35/35 if you are missing levels
3) End helps.. not sure what do you mean by a lot :) I tend to go 27-34 but one probably could go lower
4) for pvp: Great Chaos Fire Orb, Chaos Bed Vestiges, Fire Surge, Black Flame, Black Serpent, Bursting Fireball; for pve: Rapport
4 a) notice, that as pyromancer you have also perfect setup for using dark sorceries (with Izalith Staff): Great Deep Soul and Affinity are good for pvp. You can also use Crystal Chime and add miracles and sorceries (even if a bit weaker) to the mix. For pure PvE it always pays off to have Hidden Body in one of spell slots.
a bit of explanation: you can play Pyro as pure caster - but that isn't that easy, and not really that fun. You can also play Pyro/Melee hybrid - and get very smart build, whatever you cannot kill with pyromancy/spells/miracles you do kill with a blade.