Does anyone have any experience with feral cats?

I think I got myself in over my head, and I am regretting it big time. I have my mom's help, but this just ugh...
Basically I've worked at my job over 5 years, there were 2 cats. A couple ladies there feed them. Over the years the momma cat has had litter after litter, and all the kittens would always end up dying. I should have done something about it then, but no one seemed to care so I ignored it. Well finally she had a litter of 3 cats survive. Which meant 5 full grown cats. 2 wandered off but 1 recently returned. Then both the momma cat and one of her full grown babies had a litter. One litter completely died, one had 3 survivors and are now 4 months old (give or take).
So of course everyone is complaining because there are 7 freakin cats, it's ridiculous. No one wanted to do anything about it so my mom and I are getting them fixed. The goal was to take home the 3 kittens, but we only caught 2. We have 2 adults fixed, still need to fix 2 adults, and the last kitten might end up just getting fixed and released. There is a Sgt there that wants to have the cats euthanized but I am not taking them to their deaths. I just fixed them, and released them. That has been their home and they are also doing their part to keep away any other cats. Apparently YEARS ago the same thing happened, and they had the cats taken away and these new ones moved in not long after.
I am just so frustrated because everything says after 4 months old you shouldn't try to tame them. I know I have to be patient, I know it takes time and it's only been 2 days. I read that you should have a spoon attached to something long, like chop sticks and try to get them to eat off the spoon through the crate and they refuse to even do that right now. Then on top of it, we gave them flea meds as soon as we got them but of course there are still fleas EVERYWHERE in that bedroom and it is the room with my guinea pigs. My mom is coming over in the afternoon and this is all just a mess. I vacuumed up a bunch of fleas but they are everywhere, and I don't want my guinea pigs getting eaten alive because I brought these stinkin kittens in.
I'm gonna watch some youtube videos on taming feral kittens and doing more research tomorrow, just curious if anyone had any experience with that? I guess I'm just looking for someone to say I did it and it was worth it, it just took time. My worry is that we do this for weeks and they don't get any better, and no one would adopt nasty cats, and I don't blame them. I am not even a cat person, isn't that funny? I guess I am just venting because I am just freaking out, especially over the fleas/guinea pig situation.
Sometimes I wonder why I do stupid crap like this, but I didn't want those cats to have 829038290 more cats and I know I've done the right thing, I love animals, I just wish the right thing didn't have to be so stressful!
Anyways, this is Lilo & Stitch *SIGHS*
I just wanted to say as a disclaimer, I am not freaking out because they haven't made progress in 2 days, I am prepared for this to take weeks, I think I'm just overwhelmed because I have 0 experience with this, plus the fleas/guinea pig thing is bothering me so much.