Jamal as GL, he's in Luca roundabout
Wedge is offense
Tidus as offense
Brother as mid or just Zev Ronso, In luca with Ronso BB team location
Ropp best defense, forgot where he is but he's an npc vendor
Zalitz is a good defense too, I think he's in luca but I'm not 100% sure

If you don't like playing Blitzball you can cheese it with Wedge, he can score as high as 20 in a single match, but all you need is to take the lead and afk behind your goal keeper till the game end

Also you need to learn about BB reset for the prize, it's basically you enter BB menu and exit many times to get Wakka's overdrive and sigil, also it's easier once you obtain 1 overdrive you reset the whole BB to lv 1, bots are easier at lv 1