Returning player - what to choose?

[Enkidoh]

Welcome back!

To answer your questions:

1) Class is battle orientated so it doesn't really have a bearing on how the story progresses. It does however determine which city you start the game in, based on the location of that class's Guild. However, once you unlock the Armoury System you can change this class at will later.
2) This is just my opinion based on personal experiences, but I think female roegadyn are probably the least popular race. As race and gender is purely cosmetic though, and given the fact you can change your race using the Fantasia item, it's now not uncommon to see previously less popular races becoming more common as players start to experiment with races they didn't consider playing as at first.
3) It is perfectly fine to leave crafting and gathering to later - whatever class you want to play as is completely up to you. You're free to only concentrate on one or two classes and ignore the rest, or level all of them. A lot of players like to level Disciples of the Hand and Land though to as a means of providing a source of income in the game (as well as being able to infuse materia to equipment and repair damaged gear at will), but you can easily get by without doing this. So don't feel bad if you just want to concentrate on playing the game by chucking spells at monsters or swinging a weapon around.