Tentacles works well on a ST5+ player, but not on a ST3 player. It would be useless on a Pestigor.

I see that you want to take Big Hand, but you need to keep in mind that extra arms is a WAY better skill than it was under LRB4 as it now allows you the +1 to catch, intercept AND pick up the ball! Definitely one of the first skills that you want to be picking up for the team (for a ball carrier).

I would not be so quick to give tentacles to a pestigor, as they are only S4, but have used it to great effect on a Nurgle Warrior with Tackle. My first choice, however, might be Warriors with Block and Claw - but this depends on the other teams in the league - in a team of elves and skaven you would defintely take the former.

For the Beast of Nurgle, I would reccomend Break Tackle as a skill worthy of consideration, as the Beast is often a player that you want to be putting the squeeze on any catcher-types that make it through your front line. On the defense, I always leave my Beast deep with a babysitter, and then wait for the push to come through and then the beast moves to put his tentacles on whomever he can. For this reason the Break Tackle would be good, as if the player puts a TZ on the Beast to try to prevent him from moving, dodging with an AG5 would be no problem!

On offense, leave the warriors back, not on the line, and use them to make a cage their S4, and foul appearance make a good cage, and once you start to skill, up then they can be a real problem to get through!

For the rotters on the line, you may want to consider Wrestle then, as this can bring your opponent down with you when he attacks. Against slower opponents, (dwarves khemri) this can give you the edge you need.

The other rotters can be flexible depending on how you want to use them - one with kick, a few with wrestle, blockers, claw boys, maybe one or two with the extra arms. This is where your individual style will be shown.

Hope this helps.