OP for saying you don't want the cats, you are definitely doing a lot for them! A lot of people who willingly adopt cats (and other animals) neglect them by not fleaing, worming, having no insurance etc. So I take my hat off to you for doing all these things.
I think if you try to resolve one thing at a time, it might make things easier. I wouldn't keep them outside all of the time tbh.
Get an extra litter tray or two, and try to find ones that are either taller, or wider. That should stop the peeing on the side (one of my cats sometimes used to miss the end of the litter tray until we got a different type).
If having the litter trays in the kitchen are an issue, it might be worth keeping the litter trays in the shed but only if you get a cat flap, so they have access 24/7. You may find it easier to start this by leaving one tray in the house and one in the shed.
How old is the DD whose cats they actually are? Sorry if I've missed this..
If she's old enough and capable enough, try and make it a task for her to do something for the cats daily. iif the fur is an issue ask her to comb them, to get rid of most of the shedding in one go. (you can get special cat combs. If you're ok with 3 year old DD being near them, and if shes gentle - can get a special glove (think its by JML), you wear to stroke the cats, and it picks up loose fur. You could 'teach' her to stroke them.
If you can't afford this atm, ask DD (cat owner) to vaccuum every now and again.
You'll find that the worst places for fur are where they're sat for long periods of time, rather than all over the place, so she could only have to focus on those parts of the house.
In terms of training, some cats respond, some don't. But almost all of them need a routine. Use treats (dreamies are the best) to guide them to a particular spot, to get them off the counters. All of my cats, when they come in or wake up, wait at a particular spot to have their treats every day.
In terms of stealing human food, the only thing you can do is keep stopping them, and distract them and they will eventually give up. The best way I've found, is to just hold my hand over the plate so they can't reach the food. I also started coordinating our dinner time with the cats, so whilst we've got food out, they're too busy eating themselves to realise (if dinners are at different times at your place, then the treats work well for this as well)
If they do go outdoors a lot (sorry I've not seen if they do or not) let them out a lot during the day. They tire themselves out then in the evening they will just eat, poop and sleep 
Sorry for the long post, I hope it all works out for you.