3 orphaned kittens & a little asian girl

Hi, I’m not exactly little anymore, but I am taking care of three orphaned kittens that my friend found last week. Considering their physical progress, I’d say they’re about 3-4 weeks now. The tabby male is Captain, the white male w/ point-coloring is Alto, and his female twin is Arya. We haven’t taken them to a vet this past week but we will when Monday rolls around. We’ve read up on kitten care and have been using kitten formula, feeding them when they wake up and start meowing. After burping and petting them, they fall asleep and it’s a few hours until the next feeding.

I have quite a lot of worries and questions about them since I’ve never taken care of cats before, much less kittens. My main concern is their waste, because until a few days ago, my friend and I were stimulating them over the sink, and now they can eliminate by themselves but they eliminate anywhere and seemingly at random times.

I’m in a one-bedroom apartment with a kitchen and living area. I’ve put a litter tray (disposable baking pan) under a cabinet in the kitchen and, until yesterday, another litter try (shoebox lid) in the bathroom, now in the bedroom. The kittens themselves don’t sleep in a dedicated space, during the day they sleep on the couch where I make a nest out of blankets or towels. At night they sleep in a nest in the bathroom or a nest in my bedroom. Basically I make a nest anywhere and move them there to sleep.

The problem is that they will always soil their nest. I’ve gotten steadily used to doing laundry every other hour, because when I wake up in the morning, they’ve soiled their nest, and when I check on them during the day, they’ve soiled that too. I was concerned on whether or not they pee in their sleep or pee awake, but then they just move to a different part of the blanket or towel and continue sleeping. I only see the stains in the morning. Sometimes they don’t notice when they’re peeing on the kitchen floor, and they remain sitting in it until I move them to the litter tray.

Litter box training has not been very successful; I first showed Alto how to use the litter for pee and the next time he had to poo he climbed right in. But that was it, he’s peed on the kitchen floor and bedroom carpet more times than that. Just this morning, I coerced him to walk over to the litter in the bedroom and with his front paws in the litter, he started peeing on the carpet. His sister Arya did the same. For both of them, once I realized they were peeing, I scooped them up and put them in the litter tray.

Arya’s also peed and pooed under the sink in the bathroom. Two nights ago when they were sleeping in the bedroom, she walked over to a corner and peed there. Since I’d never seen any of them walk over to the litter tray in the bathroom, I moved it to the corner in which she peed (after I cleaned up). And what happened is what I’ve described in the previous paragraph.

Their brother Captain is also a big concern. He pees on whoever’s holding him while being burped in the kitchen. I can only reason that it’s because our chests are warm and we’re holding him, so he feels safe and lets go of all bowel control. When we realize, we move him to the litter tray to let him finish there. He also has a tendency to pee in small covered places, like under the kitchen cabinets. There’s been a lot of accidents in the kitchen, so I’m thinking maybe the placement of the litter tray is wrong. We use Feline Pine litter, where the pellets turn into sawdust when wet, and we scoop out the poop. I’ve heard kittens like something sandy or with a dirt-like consistency, and these pellets are equivalent to us walking on a rocky shore, so maybe the litter is also an issue.

They also enjoy crawling all over me, sometimes meowing. At first it wasn’t so bad, but their claws seemingly grew five inches in three days and now I have scratches all over. I’ve been sleeping on the floor with them so when I wake up to their meowing, they’re pulling themselves on top of me. I’ve read I’m not supposed to let them play with my hands or else they’ll misunderstand when they grow up, but I’m not sure if crawling all over my body should be addressed the same way.

I’m sorry for such a long post, but I’ve been googling to the high heavens every day for answers to my questions and they’re either not applicable or nonexistent. Instead of relying on secondhand information, I thought I’d try my hand at posting. Thank you very much for reading, any response is appreciated.

TLDR; how do I stop kittens from soiling their nests every time they sleep and actually get up to use the litter trays? (I’ve heard you need one more litter tray for the total number of cats but some people have gotten by with one or two for multiple cats)