OK, I'll try to review the different options for each player.
WD#1:
- +1ma? Could be useful to give this guy a bigger reach of the pitch, and make it an even bigger threat to all ball carriers. Nonetheless, 8ma is already plenty and with careful positioning of your players, your WD should be able to reach any strategic target on the pitch when you need him to. Better focusing on the other skill/trait choices.
- Using the double? You could go for MB to give your WD more SPPs, but then with strip ball, his job is not as much knocking players down as it is to take the ball away from them. Jump up is worth considering, yet once a WD is down, your opponent will try to make sure that he'll never be able to get up for the rest of the game again...
Guard can be nice to bring an assist when trying to bring down the ball carrier (by hitting him with two dice instead of one) but then that implies making one more leap into the cage, and also increasing the chances of having another WD being smacked in return (since you'll have TWO WDs in the middle of the cage, assuming you'll have succeeded at leaping twice, instead of one). Guard would have been nice on an ag5 WD. Dauntless is my personal favourite, but subject to one things: are there any other coaches in your league with st 4+ players likely to pick up or successfully receive the ball, like chaos warriors, anyone with st 4 and ag 3, or even bull centaurs?... If there are none, then maybe you should not bother about dauntless and go for jump up or even MB instead.
- tackle? I wouldn't: keep it for your other WD to spread the offensive skills.
Conclusion: I would definitely make use of that double, picking dauntless as my #1 choice, and jump up or MB as my #2 for the above reasons.
WD#2: Hmm, another double.
More generally, I would also make use of that double. After all, WDs can easily progress thanks to their excellent scoring abilities, so you can always get a normal skill, like tackle, later.
The reasoning for the first wardancer applies here, subject to a few points:
- I would find it pointless to give dauntless to the TWO wardancers - one with that skill is enough in my opinion: if you position your players carefully enough, the dauntless player should be able to reach the st4+ ball carrier wherever he goes, thus relieving the other WD from being dauntless as well.
- On the other hand, having TWO wardancers with jump up may be more that twice as effective as having only one. Why? Because your opponent may find himself struggling as to which guy to fould in case both wardancers are down. That is equivalent in a sense to saying that one wardancer would cover the other one and conversely when both are down.
Conclusion: so long as you keep in mind my observations for #1, any skill / trait would be good for #2, depending on your own playing style, and again so long as you actually do not ignore that double (see my general observations about the scoring and fast improvement abilities of wardancers).
Catcher:
- side step? Always nice since it makes it harder for the opponent to hit the catcher, or even profitable for him (after all, if you don't get knocked down, you could 'slide' onto an even better position to receive the ball and/or run away...). Particular useful if there are many 'hitting' teams in your league.
- leap? Very useful to avoid making loads of 3+ or worse dodges. But it is a double edged skill: that's also an enticement to make a roll without a reroll associated to it (unlike dodging and your dodge skill)... Up to you.
- pass block? Very powerful for a guy who has already dodge (better mobility) and catch (ability to reroll a failed interception attempt). If you want to play an aggressive game in a league with many opponents like to make passes (i.e. NOT dwarves), that's the best choice in my opinion.
Conclusion: each skill has its own worth, depending on your playing style and the type of opponents you are likely to face in your league. I might lean towards MB since that second WD is likely to pick tackle as his next skill (see my comments on MB for WD #1) and therefore will have the job of knocking down people more than his colleague in your team. Yet, the other choices for WD #2 are just as good in my opinion.
Lineman:
You could give 'offensive' specialised skills to that guy (like diving tacke, or dirty player...) but then the more specialised a guy, the more your opponent will be enticed to boot him out. I suggest not concentrating such specialised skills on one guy, at least not until he has reasonable protection - give him block (or maybe dodge, yet it may be not as effective in keeping a guy alive because of the existence of the tackle skill, and also not that effective for him because your guy does not need to be as mobile as your DP since once he's used his kick skill during the kickoff, he does not have the same need as a DP or DT player to move around to do his job during the game).
Good stuff all around, plenty to think about. 
