I'd go for:
------------------Moore
O'Connor---Dean-----Craig-------Logan
Forrester--Reeves--Douglas--Donaldson
----------------Saunders
----------------El Alagui
Subs: Lee (if not fit then Gounet), Legge, Fredericks, Redwood, Diagouraga, Forshaw, Weston
I'd go for a 4-4-1-1. It was our most successful system away from home last season, we looked better when we added a bit of width in the second half against Wycombe, and it seems like the best way of fitting Saunders, Forrester, Donaldson and El Alagui into the same team. Donaldson has played wide before and is always effective running the channels and setting up chances from crosses when playing as an out-and-out striker, so should be comfortable there.
I'd start with Reeves instead of Diagouraga, as I really feel we should be able to dominate the midfield, and Reeves allows us to get our quick passing game going more efficiently than Toumani, who will be more needed in games where need extra experience and steel. Also I rate Reeves over Forshaw. Walsall barely have a squad, and have been signing League 2 rejects and playing players out of position in pre-season - we need to take advantage of this and repeat the domination we showed against Wycombe, but obviously not let a repeat of that Hereford game at this stage last season happen!
I think our best option at left-back in this game is Logan, but hopefully we can give Redwood some game time as a substitute to ease him into first-team action. I'd play O'Connor at right-back, as Fredericks has only just joined the group, but as Rösler has said that KO'C is not 100% fit yet, that gives a perfect opportunity for Fredericks to come on after 65-70 minutes.