Just started FFX..few questions!

Well, recently I got FFX.. to be honest, it's my first FF game, besides XI which I quit a long while back. I'm not sure if the sphere thing is in the other games, but I am so confused with the sphere system that I'm at the first Blitzball tournament and I have put only 1-2 points into each of my characters.. so I have some questions:

1. How do I distribute my spheres.. like each character has 1-3 routes to start on, and I just don't know which one to go to. Since there are locks, does that mean it's better to save points and go the locked route?

2. Someone told me everyone can actually get all the skills in the end. Is this true? If so, how?

3. I don't know if this is like some other RPGs, but for some others there are things you may pass that you are not able to return to, are there any of these in FFX, anything you can't undo/redo/go back to? (wondering about the spheres too)

4. Should I be leveling up each character equally?

5. And one of the most confusing parts of the game.. items. How do you tell which sword is better than another? Do they have stats? Or just the extra abilities (ie: 5% str).. armor too.

6. Is Gil important? Is it hard to attain?

I just want to get the most out of the games I play, so I don't want to miss anything important >.< And it feels like I am missing something with this whole confusion of spheres and equipment..

1.
it doesnt real matter, you eventually ge key spheres which unlock those spheres but just follow the path that seems natural to the character.
2.
it is possible to get all abilities for every character if you complete the whole sphere grid.
3.
you can return to every location and i dont think theres anything 100% unmissable but be careful if you have the english version because there are dark aeons gaurding certain locations. dark aeons are superbosses and wil take a lot of leveling to beat.
4.
id reccomend that you do so. because some parts of the game force you to use certain characters and it would make things a lot easier for you.
5.
the weapons arent like on other FFs and the only way to make yourself do more damage is by raising strength or getting something like strength +10%.same with armour. the only weapons that do extra damage without these things are celestial weapons. there is one of these for each character and they are very hard to find and power up so i wouldnt focus on them yet as they are unecassary and will only be needed for certain superbosses(not 100% needed but they are reccomended.)
6.
gil is just like in the other games(apart from FF8.) monsters drop it and you use it to buy items and weapons and various other things.

i hope you enjoy the game.
BTW. youve been on this site longer than me and this is your first FF? youve got to buy the rest because in my opinion this is good game but games like FF8 and 9 and a lot of the old ones are better still. i hope you become a massive FF fan like me and try as hard as you can to get every FF.

Yeah.. like I said I was here for FFXI, way back when it first came out, but I didn't like the MMORPG style of it. But I'm loving the FF's.. can't wait to play 7 after watching advent children...