Looking for some guidance on resources of how to begin analysis or how to build a business of this sort.

The IRS doesn't trust you to report accurate information, so the 1099 from the property manager is checked against your filing.Any company that does more than $600 in business with you should issue a 1099.

Usually most franchise models in other business environments have the whole package.

this is basically the business credit coaching partner that works with you over the course of 12 mos. to help you build up business credit for your company. 

Don't quote me on that, but it's easy to look up the IRS regulations.I recently had a conversation with somebody else who is planning to start an STR business. 

Should I have one website advertising both and have business cards list that I offer buy/sell realestate services and PM services.

I normally advise that people start a business as a sole propeitor in their first year.If it is successful and something you want to continue, then have a conversation regarding entities.

Trying to bring this back to the top.

To support my seller and seize a valuable opportunity, my business partner and I decided to purchase the property ourselves.

And when you buy a 2-4 unit you can use 75% of the rent that the appraiser says will bring in on the units you will not be occupying.