That is a nice haul! Those should all be able to clean up and be users. Even that big wedge (the joseph elliot I think) has lots of life left in it, but its been well used. No frowns, and the rest look like they have seen minimal use. The first thing will be to get some oil on them to stop any continuing corrosion, then check the scales. they all look like natural materials, so I don't think any are celluloid, but if any feel like plastic, give them a sniff. a vinegar/camphor smell is bad, and those scales should be removed and tossed immediately. (celluloid breaks down over time, and the gas released is very corrosive)
As for cleaning, if you don't care about any echings still on the blades, then a brass tumbler would clean them up quickly, otherwise steel wool would do the job. Scales can be replaced and don't really drop the value of a good blade. Personally I think they are all worth restoring, Looks like it was a well loved set at one point. too bad it was left to rust, but at least you got it before then!
Those are some very nice looking blades man, Lucky find! My luck is never that good.