Raised the 25% down payment through a partnership with family members (my parents and my two oldest children).

If we don't go the LLC route for now and just make a general partnership, will we have to register the partnership also in both Ohio and California?

I would consider partnerships in the future.

Partnerships are tricky and you can't always be the one making the decisions, partner has to win too.

As a general rule, each entity that files a separate tax return (partnership, s-corp, c-corp, etc) will need its own QBO subscription.

The broker’s expertise in structuring these documents can significantly enhance the investor’s chances of obtaining the necessary funds.Communication is another cornerstone of a successful partnership between private money brokers and real estate investors.

And do you and your sister have a partnership agreement that spells out how you split the profits if you sell it or if you do BRRR?

We are hoping to avoid doing any sort of partnership and maintain a single member LLC, but searching online hasn't been fruitful.

They are in partnership with Obie for Fix & Flip type insurance (builders risk, etc).  

Use your house hack as a conversation starter to open doors to mentorships, partnerships, or off-market deals.Good luck!