We have Dorn, Tansey, Owen, Sneyd, Ellis and Seymour.

Only 3 of these willbe required per game full back and 2 halves.
In the modern game backs rarely take the substitution spots, so we are going to have 3 disgruntled players this season.
Who do you think should play 1 6 7
I will go Tansey, Sneyd and Seymour.

Tansey
Sneyd Seymour

Owen will not be back-up full-back. Reynolds will.

Owen will be back-up winger with Clare being the other.

Agree with that, although Ellis did seem to improve a bit after he was dropped.
Dorn I feel will be on the bench as an impact player

It's a nice conundrum for the coach to have, next season he wont have to play Hauraki at halfback if one gets injured or looses form.