Cat health issues! Fleas and tapeworms.?

Alright.. where to begin? I live in a two bedroom apartment in florida with 2 other people.. each of us had a cat. Originally it was just the two kittens (who are now four months old) but then my other room mate brought home her mother's cat when she moved. A few weeks later we started noticing fleas. So the kittens were dewormed and I bought a flea treatment for the kittens.. A month later now though, they have tapeworms again. I called the vet yesterday to talk about getting a shot for treatment but she informed me that it's pretty useless before dealing with the fleas. I purchased a spray for the carpeting, furniture and baseboards of the walls..manages to apply it yesterday in the living room at least for the first time.. and vacuumed and disposed of the contents out in the dumpster in a sealed bag.. changed the litter boxes and wiped them out before refilling.. Here's the real issue though.. my room mate (with the 3rd cat) is a horrible pet owner, really.. She barely pays any attention at all to her cat, and even though she has fleas.. has not brought her to the vet, combed her, or bathed her.. she rarely changes the litter box (I have to do it for her) .. and the damn cat isn;t fixed.. it's a girl.. and mine are two boys 4months old.. Let's make matters even more complicated still, she's invited a friend of hers to stay with us for a few days now, with NO warning whatsoever.. not like I had an option to say no without being a total dick since he was already here with all his luggage and such. There just could not possible be a worse time for her to do this, really.. he seems like a polite person, but since he's in the living room now.. I don't know how I'm going to even begin to deal with the fleas.. The spray I have is toxic to inhale.. or absorb through skin or membranes.. so I have to lock the cats in the bedrooms to apply it in the living room.. and be sure to open the windows (we are on the second floor) to air out the apartment while it dries.. I don't want to put off treating them any longer than I have to, since the worms in the kittens stools are about an inch.. inch and a half long! Gross, I know.. and I feel horrible about it, I really do. I want to give them a bath with flea shampoo I had purchased.. I may still do that anyway tonight.. and then apply the advantix (I think that is the brand) I got from the vet. It seemed to rid them of fleas for about 3 and a half weeks.. before I noticed them scratching again. I'm just really aggrevated.. I want so badly for her to be out of the apartment, or at the very least to be rid of her annoying, neglected siamese cat. Someone like her should not have a pet in my opinion.. there are many days she forgets to even feed her.. and so I do that too.. along with picking up after her hairballs, and cleaning the waste she leaves behind when she poos outside her box on the kitchen floor! I spend so much time catering after her animal.. and she KNOWS we have a flea problem, but she invites company over without even asking first. I don't know if maybe I'm over-reacting.. but I don't think I am.. I didn't get the chance to tell her about the worms yet, I just noticed them yesterday morning.. I guess I'll just text her that info. What should I do? I'm overwhelmed.. If I give them a bath with the flea treatment and then apply the advantix later after they have dried will it work okay? Or should I wait to do the shampoo and just apply the liquid treatment to the back of the necks on the skin? I need to at leats get them off of them so I can take them to the vet.. I don't want to wait! But with the company here, I feel I have no option.