I am not sure if ammonia is the right choice. If in his mind it is close enought to dog pee he may feel the need to mark it himself.
What sort of traing are doing ? My experiance is that traing is as much about teaching poeple about dogs as it traing the dog.
He hasn't had a problem holding it until he can go outside, since the first couple of weeks after I got him. Doesn't leave the solids in our yard, unless it's urgent. Guess we'll see if he doesn't know the difference. Reasonably sure he won't make that mistake. Doesn't pee on or near the toilet, and he's seen me use it many times.
I've got a pretty good handle on the training, last one turned out well. This one is just at a rough age. I've read about all kinds of tricks and shortcuts to get a certain desired result, but some seem a little cruel, others tend to abuse the dog's trust in your judgment. Basically, if you can anticipate a problem, and stop it he'll learn not to do it in the first place. Correcting after the fact, doesn't really do much. He knows your pissed, but not too sure about why, even if you rub his nose in it. Could have been hours ago, long forgotten, dog just learns you have a mean streak.
Walking him... Well, mostly I just let him do his thing, it's for his benefit. But, if gets into pulling and tugging, we change directions, take a different route. New territory, which needs to be explored more slowly and carefully. Also gets him off the scent trail, which I believe is why he feels a sense of urgency. When he's pulling to the sides of the path, or we are near people, or other pets, I shorten the leash, to where he needs to stay close to my legs. Yeah, he gets kicked occasionally trying to cross over in front of me, his choice, he'll learn.
Sit, lay down, and up...
Sitting, started by getting him to take the position, holding a treat in my closed hand, speak the command. If he stays in position and focused on my fist (of course, he knows there is a treat wait), he gets the treat. After he got that, I snap my fingers and speak the command, and hold up the closed hand, no treat, he gets it later.
Laying down, started with the treat in my hand, but one finger pointing down, speak the command. At first I need to actually touch the floor, holding the treat down where he can't get to it, without laying down. Sometimes had to help him into position.
The up part gets him up from laying down, but usually he sits, same as the last dog, but not a big deal.
After they get the positions and commands, they have to do multiples to get a treat, and eventually need to go through the whole routine, in whatever order I choose. Jake responds to either voice or hand gestures well, but a little slow when distracted (in public, visitors), but takes the proper position eventually. Should improve with maturity, did with the last one. Same with getting him to stay, and not follow until told. Just not ready yet, still has a short attention span.
There's a few more things, and I've had some success of assigning commands to some of the behaviors I observed, and thought amusing or useful.
I'm by no means an expert, nor what works for me, is guaranteed to work for other people, probably left out a few details, that I don't even think about when doing. But I do have some experience with animals. Figured I share a little, might help.