Ask HN: Building several small companies, how to incorporate them?

I am going to prototype a few really small lifestyle businesses. Just little companies to try and generate some income. I want to make sure I am protected from liability, but due to how limited the income will be, I don't know how to proceed.

These will be small companies and projects. Does it make sense to just incorporate one entity and then run the companies under a single umbrella? This would open other companies up to the liability of all of them?

Should I make a single master entity, and then have small subsidiaries? What makes sense for operating a few small lifestyle businesses, while limiting liability?