Cripes you've really got your work cut out for you there! Its hard enough if all the seedlings were in a pot just together but to have that other big plant in there as well with its roots tangling up everything.. difficult. It looks like a couple of the seedlings have a little space around them, could you gently prise or maybe cut them away and bury those ones up to their armpits in new pots. That will stabilise their fragile stems. The ones that are hard up tight to each other perhaps they could go in your big pot together and see who makes it. Bury them as deep as you can too. The damage may be too much for them but I'm always surprised at just how much these little weeds can survive, so I always think its well worth having a go at saving them. If nothing else its good experience and you never know they could come good - win win either way.