BTW, there's no such thing as "barely cooked" ravioli. They are either undercooked, cooked, or over cooked. Cooked is a very brief window.
Holding par-cooked ravioli is not much of a time saver. Holding un-cooked ravioli frozien can be a good thing for a lot of reasons. Make your dumplings on the small side, don't over fill, and all will be simpler.
When you make the ravioli, transfer them from a board to a sheet pan lined with parchment or a sil pat, and dust on both sides with corn starch, before freezing. That will keep them from sticking together while they freeze.
When you cook frozen ravioli, they'll want to clump and stick together, even more than freshly made raviolis. That's partly just the nature of frozen pasta and partly the corn starch. But, you can't have everything.
The solution is to have several pots of water going, cook in batches so as to avoid overcrowding, stir while cooking, and oil or sauce immediately as they come out of the pot.
Once they're sauced, they'll hold long enough for you to fill the pan and get it to the chaffer; while you prep the next pan. To preserve the appearance, don't put the ravioli down more than 2 layers give or take. Pans which are too full make it difficult for diners to get an appropriate amount of sauce; worse, it looks more cafeteria than catered.
Baste one last time after the little guys are in the pan, and get some herbs -- even if only parsley-- and some toasted pumpkin seeds or pine nuts down on them just as they move to the buffet line. That will make them look very fresh. Sage sprigs would go very well -- if you can trust the diners not to try and eat them whole.
Your group size is largish for working with my methods -- which are as labor intensive as they are quality oriented.
If you want to go that way, you may indeed need someone to do nothing but cook and run raviolis from opening the line all the way through the crush -- which for 70 will be something like 4 no. 1 pans. By the time the buffet line is picked over and the other pans need refresh and refill, you should be able to use her (or him) for other duties as well.
Hope this helps -- if only as another way of looking at it,