The GIS map designates it as a single-family dwelling, but the property is clearly set up as two units, with separate HVAC, electrical systems, etc.My main question is: Would it be possible to obtain a permit to legally convert it into a two-unit property?

It helps protect your personal assets and keeps your business operations separate.

Purchase price: $280,000 Cash invested: $75,000 Multifamily building containing 4 separate units each with 2 beds and 2 baths.

Have separate mailboxes for each.

This could give the ability to have a better and higher appraised value along with selling it separately from the main structure (main SFR or SMF).

There is one book for 49 states and a separate book for California.

@Sabrina Dace, be sure to separate the breakthroughs he teaches verses the real estate. 

I think in Austin, you could find solid young professionals, but a lot of owners of room hacks/house hacks find it difficult to separate owner to tenant and co-tenant relationships.

Keep personal and business finances separate.

@Eric Lahoda, is it typical in your market to charge fees for those items separately?