I don't beleive this is true based on the IRS site stating you don't have to issue a 1099 if you are "not engaged in a trade or business."  

Additionally, is it reasonable to request the current leases and what I believe is called the rent rider form (please correct me if that's not a real thing) prior to making an offer?

At the current price, adding the additional lots would make them about $30,000 per lot, depending on the price of the additional utilities that need to be added. 

Also, make sure there aren't additional restrictions on the property condition, compared to a conventional loan. 

I went to a learn-on-the-site program that our local REIA had recently.  3BR/3BA house, owner is probably in 145K after fix up (I know the purchase price, don't know what was spent to get it ready after purchase) and a handful of years later it's now worth 190K. 

They require a site plan to get that started.Has anyone had any experience with this and have done it successfully?

A good way to find deals is by connecting with local real estate agents, wholesalers, or checking out sites like Facebook groups and Craigslist.

Be sure to have a detailed discussion with your lender to confirm compliance and explore all available options.Feel free to reach out with additional questions—I’m here to help!

I charge fees that create additional income.

Aside from that the biggest value add areas I see are as follows: Kitchens, Bathrooms, decks/patios (if added), additional rooms/bathsKitchens and bathrooms tend to be the go-to, but all of those can help you get the most bang for your buck. just keep in mind that if the area is already of high quality, then it may not be the best area to spend the money vs something that is blaringly in need of an update.