Thanks for this great info! It sounds like maybe our best bet is to start with him in the living room and then, in a few years, let him in the bedroom once he's grown and trained and can be trusted.
Here's another thing that's confusing. Can he be locked in his crate all night? Or do we have to get up around 2 am so he can pee? Or do we leave him in the expen so he can sleep in the crate but have access to the grass patch when he has to pee? Do we take away his food and water at around 7 o'clock so he won't have to go overnight? Sorry for all the questions!
He may need to potty during the night in the very beginning. Kodi only did a couple of times in the first week or two, Pixel didn't more than once, and Panda didn't at all... but she was a bit older when she came home.
Whether you lock them in, or give them access to a larger space, like an ex-pen, with a potty depends on a couple of things. Whether they will respect that space and stay IN it (some Havanese are climbers... none of mine were), whether the breeder has done enough work potty training them that they are TOTALLY reliable in finding the potty if left unsupervised in the larger, ex-pen area, and whether you can are willing to get up with them fairly early in the morning.
I hae RA, and my sleep is very important. I found getting up with Kodi a 6AM to be exhausting. So after just a couple of weeks, when we were SURE he would both respect the barrier, AND was totally reliable potting in his box, we just left his crate door open, and he had the run f the whole area. That meant that he was able to take care of potting by himself, and I was able to sleep until 7, then come down and feed him.
The girls were crated straight through, but they have always been better about sleeping in the morning. We did teach Kodi to eventually extend his "sleep time", and he will wait until 7 now to potty in the morning... but rarely a SECOND longer than that.
He is ALWAYS the first one up in the morning.
It is MUCH better, for a number of different reasons, to feed puppies on a schedule (usually 3 meals initially, then most people drop down to twice a day later) Leaving food down all the time, and allowing dogs to "graze" leads to fat dogs and picky eaters... neither of which is a road you should want to travel. It also makes potty training more difficult.
OTOH, I am COMPLETELY against removing ANY animal's access to water for anything other than a medical reason. It goes against everything I've ever been taught about animal husbandry. Dehydration can cause a host of long-term health problems. I'd rather have to get up and let my small puppy pee during the night than take a chance on sending him to bed thirsty.
I would not "get up at 2AM" to let the puppy pee... If you won't be able to hear him from your bed room, set up a monitor if you need to. If you GET him up consistently, you will be "training" him to pee in the middle of the night. Of course you don't want to make him pee in his bedding, but the goal is for him to sleep through. So if he doesn't wake up, let him be. None of mine woke up consistently at night, even during the first week. Before week 3, none of them ever woke up during the night again unless they were stick or something.
Finally, as far as the "grass patch" is concerned, that would not be my choice for an indoor potty option. I've tried a lot of different things, and the problem with all the fake grass is there is NOTHING that really gets the smell out of them, no matter how often you wash them, or what products you use on them. I couldn't stand the smell in my house!!! By far, my favorite potty option is a litter box, with or without a grate over it. Second would be a disposable pee pad with a grate over it.