Sorry, I don't have lightning, but I'll try.

Sasuke I think should be farther back because his Kirin starts combos. Whoever ends up in the back is really up to how crucial they are; on your team I think it goes Gai > Sasuke > main > Asuma, but it depends on your skills.

You don't really have defensive ninja besides Gai, who leeches, and even then he dies fairly fast. I personally prefer someone with clones, healing, etc. like Kabuto (who has both). But if you take people out fast enough that that's not an issue, you're good.