I'm in Baton Rouge, not Covington, so I'm not 100% certain of what's going on over there. However, I did drive over to that area recently. There is still a lot of damage in that area that needs repairs/reconstruction. I would venture a guess that any and all additional help would be put to use and appreciated. That area is getting back on it's feet a bit quicker than N.O., but they are a long way from being back to "normal".
It would strictly be a personal choice as to whether or not to bring the additional people unpaid. They would certainly be put to use, but as to how much time/effort they can afford to put forth without pay is a judgement call for them.
As for items to bring, I believe most of the stores are getting restocked on groceries, etc., so there may not be the need to bring a lot of additional items. It's more likely they are in need of warm bodies to help with the repairs/reconstruction than donated items, but you may want to confirm this with the local church if you can get any information out of them. The folks around that area tend to be a lot more resourceful than what was seen in N.O., but right now they just don't have the manpower to make a lot of progress.