Buff Order? Iz that a new Feature?

I think the buff order depends on the placement. You can experiment with the Kakashi clone after placing your ninjas in specific orders to see who gets the water buff when.

I believe it is based on placement order. (ie. which character you place on the "board" first.)
This works for regular buffs and shields. (eg. Iruka's stat and shield buff - if you place Sage Naruto/Wind main with clones before Iruka - position does not matter), his buff will affect the clones as well. If you place them after Iruka, then his buff will activate before the clones activate, thereby missing out)

Since AF's water nin buff affects 3 ninjas I would place her last on the "board" I would presume that it will buff the first three ninjas placed.

It'll buff based on placement order, but as soon as you revive and target the ninetails the second time, it will begin randomization again.