You can choose any class,what matters are how you play and assign you stats later on.The class choosing system is just for better starting stat.Personally i rather play melee since that is where the fun of the game.Sorcerer/Pyromancer are just like ur average magician in lots of game lolz Although they do have some handy spells.Hell you can use magic / sword too if u want but assigning stats for that is going to be hard.BTW i know u type Stfu means sifu somehow but STFU more like Shut the f up lolz  
can but got level gap and some ppl can co-op and some can't :/

str n dex, depending on ur weapon. I mainly used it for weapon requirement.
vitality 30 should be enough. and for endurance, best if u can cap 40.