Or is it as straightforward as buying the multifamily property, putting it under an LLC, and then registering that LLC in your state as well?

If you search for groups with "wholesale" or other keywords you'll see them, there's a lot.

That sounds pretty straightforward and we've got something similar here too and it's not bad. 

Doesn't mean its a necessity to have it formed here but it is a fairly straight-forward process. 

Keywords go a long way even with an OTA listing. 

This separation allows you to manage risks more effectively, ensuring your personal credit isn’t impacted by the ups and downs of your real estate ventures.Building business credit is more straightforward than most people think.

The house build  course is pretty straight forward  and walks you like a baby through  every step from finding the land and entitling it to building and selling.

Quote from @Nathan Gesner: Buying a house is straightforward; managing it can be a whole different challenge.

That seems to be a straightforward solution.

The straightforward method is to do everything yourself, as in my example above.