I have a 2500 sq ft 3 bed 2 bath 2 living 1 dining and one bonus room rental.

Disadvantage: Additional risk exposure by involving the primary residence?

You don’t need an entity to use sec 179.However, there are income limitations, business use limitation on auto, and potentially deduction limitation on auto deductions based on type of auto.If sec 179 doesn’t work, you can also use bonus but it has its own threshold and requirements. 

What should I do: studio, 1bed, or 1bed with bonus room (possible home office)?

What should I do: studio, 1bed, or 1bed with bonus room (possible home office)?

If you take a shorter term approach such as flips/assignments, you're also able to reduce your risk and exposure. 

We listed our first property on both Airbnb & VRBO to get maximum exposure. 

Real estate folks are learning a current work around by selling and in the same year buying another property and using the bonus depreciation (from a cost segregation study) in order to offset the capital gains on the sale.”

Therefore able to leverage scale and buying power across projects. 2) you get bids as you described and divide up the equity based on how much work they have into it. 3) to incentivize quality you must reserve equity of the profits for a bonus pool.

Property Management to collect rent, leases and etc would be an added bonus.