talents 2311 or 2211
kurenai main hinata
x x x
x x iruka
or
kurenai main hinata
x x x
x iruka x
or
kurenai main hinata
x iruka x
x x x

i suggest placing iruka in a higher moving order because he can interrupt in the very first round.
if you place him in the last moving order, he can only interrupt the ninja on move 4 of your opponent, and if his intiative is lower than that ninja on move 4, he cannot interrupt anyone.

also the reason why i would place him in the bottom row is that, most player have ther ninjas either in the top two rows or the bottom two rows, so the probability of them having ninjas in the middle is extremely high, therefore they would all * up on him

In the arena, your initiatives will be taken into consideration, and for most time winning/losing is dependent on that in the arena since no other stats are in effect.

Also, not only that having a good team is important in battles, you need to be tactical with when to use your mysteries, whose mystery to use, and who to use it on.

For instance, if you are facing a lightning team with their main on position 1/move 1,
your iruka will not be able to interrupt his mystery because he has a lower moving order. In this case it is recommended for you to use hinata's mystery in the first round which will allow you to dodge almost all of their attacks.

If their lighting main has a lower moving order (move 2, 3, 4) you c*e iruka's mystery to prevent them from using theirs in the first round.

Another thing is, when you see a team you should think to yourself, who you want to kill first.
For most cases that'd be their main (except for earth) because wind and lightning are high damage causing classes, and fire & water are controlling + condition causing classes.

http://4.bp.blo*.com/-v7z_C2JrYEQ/UZVbDcOolMI/AAAAAAAAD9I/uyFIcKesiI4/s1600/emoticon-crying-tears-of-joy.png
lol don't use auto in pvp, even if you have a very decent team the winning rate is going to be like 10% or something