Well for starters, castration only prevents unwanted litters of puppies ...... ANYTHING else needs correct training and clearly these little dogs haven't got the message that the ONLY place they should be urinating is OUTSIDE. How old are these dogs because housetraining a puppy is challenging with some dogs, and if older, even more so. And even more so if you have taken on 2 puppies at the same time!!
Before you get tough on these dogs, you really should collect some of their urine and take it, fresh, with them to your vet. If they, or just one? has some medical problem going on, no amount of training is going to work.
So having ruled out a medical condition (rarely would it apply to both), get back to puppy one. NO PEE PADS (and if you have ever used them, you have to untrain using them which only suggests to a dog that it's fine to empty indoors). After every nap, OUTSIDE before they do anything. After every meal, OUTSIDE. After short periods of playing, OUTSIDE. If when it's been a reasonable time since either last emptied, and they don't, then bring them straight back in (after about 10 minutes) as there's no point hanging around out there as they won't have the faintest idea what you want, and will find other things to do. Instead of letting them have the run of the house, keep them in the room by the outside door and the moment either goes to squat, say NO! and taken them both back outside. It's doubly difficult with two to train btw. which is why people say only get one puppy so you can concentrate on training one. And for now, I'd take them outside part-way through the night so that eventually they should get the message. Prevention/avoidance. And NO castration because this is down to training and if you expect it to be a cure-all, you'll be disappointed.
And clean up where they are marking properly. For now at least, if you aren't right there to supervise, you may have to crate or otherwise confine them to stop all this.