Question regarding sous vide cook - chill for duck confit

Well... I haven't tried what you are asking about, however I have made duck confit several times. I think that a little reflection will advise you against doing what you suggest.

Forgetting the brining, for the moment, when you sous vide the legs, you're cooking, tenderising them and pasteurizing them at the same time, aren't you?

Well if it wasn't for the pasteurising, there would be nothing to prevent you doing what you suggest, I guess. However, once you break the seal on the bags, bugs will get onto the surface of the legs. Although they'll be killed when you sear them (why the "off" by the way?) you can't do this in the bags, so you will have to let them cool before packing into bags again, won't you? And in that time, there's no guarantee that no pathogens start growing, is there? Obviously, you could, theoretically do the searing and then re-pasteurize for the minimum time needed to reach safe levels of C. Botulinum. But then the recipient would still have to grill them to get the skin nicely crispy again. No... on balance, I think the best thing is to give the lucky recipients cooking instructions from sous-vide.

I suggest something like:-

1. keep this at temperatures below 5°C until ready to be used.
2 Place bag in warm water to melt fat and juices, cut bag, strain off, separate fat to use for cooking potatoes. Keep juice to add to stock/soup as it's pretty salty.
3. Place confits on a grille over boiling water, cover and steam to defat and desalt for 15 minutes. Meanwhile pre-heat the grill.
4. Transfer the grille to the oven set at 240°C and cook for 15 minutes, skin side up. Serve with potatoes cubes fried in the fat from the confit.

If you wish to sear them and distribute them, one could always not vac pack them and simply distribute them from a chiller in a food container, thus removing the worries about anaerobic bacteria. If you are worried about spoilage you could even freeze them after they have cooled (not vac packed during cooling) then give them out with instructions on how to reheat/crisp from frozen.