I'm working on closing a 28 unit mixed use property in WA State using seller financing once we get the additional capital required by the seller.

In addition, doing fewer deals than that will most likely mean that they don't have a legit team of pros to back you- PM, GC, Plumber, lender, etc- if they aren't feeding them constant business, those contractors won't drop their current jobs to help you in an emergency. 

I've heard of folks using the equity in their rental properties to purchase additional properties and I'm trying to learn if this would make sense for me.

Additional Context:- I'm usually a DIY everything guy because I grew up doing construction and farm work.

In addition to the solid list from Joshua, Typically LLC costs.

If you decide to go this route, you could inform the tenants that they will be responsible for a separate monthly utilities charge in addition to their rent.

Additionally, the price was initially listed at $795,000 and is now down to $645,000.

Do they charge any fees in addition to their asking price for properties?

What do you mean by the additional $18/sq design fee was not included? 

Do you intend to purchase additional properties?