Modern bathroom pods are very easy to install and come in pre-configured sizes. They're literally just plug and play.
After that, the only challenge is making sure you have plumbing connections at the bathroom and kitchen sites. But modern pex plumbing makes that pretty easy. You're just running flexible rubber tubes from the multiplexer. In this sort of design, I'd imagine you can just pre-print the holes for the tubes, or punch through where needed.
Modern houses are very easy to install and come in preconfigured shapes. They ship flat packed components and drop them on site for low skilled workers to build. They include things like bathrooms and kitchens as part of the build.
After that, the only challenge is making sure you have plumbing connections at the bathroom and kitchen sites. But modern pex plumbing makes that pretty easy. You're just running flexible rubber tubes from the multiplexer. In this sort of design, I'd imagine you can just pre-print the holes for the tubes, or punch through where needed.