The quick answer is no, but best to read this article as various states have certain requirements: https://www.zillow.com/learn/do-i-need-an-agent-to-sell-my-house/

I'm from Leesburg, and I can tell you—multi-family is a solid choice (piggybacking the previous comments which I agree 💯), especially with that live-in/rent-out, house hack strategy.

Or once I finish building the house and get the C.O.?

@Jerry Velezstrongly recommend against doing this.start with a house hack instead.make it your mission to house hack.did i mention house hacking? 

I am well versed in pretty much every facet of Real Estate: house hack, LTR/MTR/STR, multifamily, and fix and flips primarily.Aside from that I am also (somewhat) a serial entrepreneur, having started and sold multiple business' over the last 15 years.I also meet with 20+ professionals every week, through referral groups, meetups, and just 1 on 1 sessions trying to get to know people and make connections.I would love to chat with you if you are looking to meet people and get more information about real estate in San Diego!

He was also in escrow to sell the house as a busted flip, as-is.

I would also mention that once you have invested in Utah, I recommend the Utah Rental Housing Association as a resource.

Or find a deal first then market it to buyers, then offer on the house and create an agreement with the seller & buyer?

As population grows, housing demand increases, driving rents higher.Rapid and Sustained Appreciation: Not all cities with growing populations appreciate rapidly.

I have a seller who wants to sell a house that is worth roughly $830K.