They potty the most where they eat. So if you feed them in the loft you will contain some of it. But you will likely never completely potty train them. They go where they want. But I wouldn't make the main floor smaller. They need room to run around.
Mother daughter pairs work very well. Usually, since Mom is older and bigger she is automatically the boss. Sometimes "teenage" daughters will challenge her for dominance but it is usually settled quickly and without injury.
He looks like a young California pattern piggy. It's one of the newer varieties. They look like himalayan but have dark eyes. The body can also be red or cream. The points come in more as they get older. If he doesn't develop points, he could just be a dark eyed white with dark ears.
Be aware that weight is the main issue for anesthesia. The smaller a pig is, the more difficult it is for them to maintain their body temperature under anesthesia. That's why most vets will want to wait until they're a little older.