I agree on bringing a vet to the picture here for the sake of the kittens under your care.
I've dealt with resistant parasites in kittens and that does not necessarily mean you got worms but it wouldn't hurt to deworm yourself once the cats and kittens get their treatment.
I've rescued many cats and usually they present the typical rice like looking parasites and I take them to the vet. Since you have many kittens maybe you can negotiate a good deal for all of them because we know it's not easy to pay the vet bills but I think it's necessary in this case.
My former vet (former because I moved) used to treat a litter for one price since they were rescued as a way to help me help the kittens.
It's good that you have a technician to help you but now that one of them has a swollen butt and more problems it's way better if you have them be seen by a vet.
It's all a matter of luck and search I had to go way off my area to find a vet that would help me with my rescues.
You probably know that with certain treatments for worms you have to keep them very well hydrated.
I really really hope your kittens and cats get all healthy and parasite free very soon.