I am new to real estate investing, I have not talked to a lender for pre-approval because I am in the beginning stages of learning.What is the best business structure to use for a rental property business, Sole Proprietor, LLC , or corporation?

A room full of bridge, construction and DSCR .

I am trying to figure out how J and Dave got to $65,000 in the following section (I am reading the eBook version so page numbers won't correspond with the physical book):  Towards the end of Chapter 2; "Finally, notice that the owner equity in this business totals about $65,000; because John is sole owner of the business, that $65,000 is the value that John transfers to his PFS and can claim as his ownership value in the company.”Everything up to this point was clearly explained on how they got to the number, except this $65,000.

We know there are other STR owners blocks away from us and theirs opportunity to meet them as well as other business owners?

Yes, all of the above, some people will continue to pay for a full service agent, some people will pay for a discount, some people will forgo agents all together, I think we will see alot more variation then we currently see, but just like any other business there will be tiers, Ritz, Marriott, Courtyard, Fairfield inn but for agents. 

My renovation business -    of these previous 18 homes produces 120k/yr salary. plus ~100k/yr equity added. monthly Cashflow increase of 2100-2400 each year (approx 30k cash flow increase per year).    

Here are my top picks: (Disclaimer: I personally struggle at using these platforms as often as I should whether it's for real estate or for my auto reconditioning business)Facebook: Great for joining investor groups, keeping connections up to date.LinkedIn: Ideal for networking with other professionals and establishing yourself as an industry expert.Instagram: Perfect for showcasing properties through high-quality photos, videos, and virtual tours.YouTube: Powerful for posting property tours and educational content to attract a wide audience.Twitter: Excellent for sharing real-time updates and engaging in industry discussions.Which social media platforms have you found most helpful for your real estate business? 

Depending on the project's size, construction might take around a year.

Now if he gets you by the hand and shows you how to buy with no cash and credit, and you are able to buy, then his snake oil is worth it weights in gold, but he will have many excuses his business is selling snake oil not real estate.