@Alvin UyI see some a couple of pitfalls:1) Is this second unit an ADU or is it actually a duplex lot? 

The properties may need some cosmetic update but not looking to do any major value add.Given then these will be investment properties, are there general pitfalls to be aware of in term of the refinance that may limit the amount of cash I could potentially pull out?

What are some textbook pitfalls or red flags to look for?

I understand having to check the zoning laws and getting a permit - I'm curious as to any pitfalls that you've run into while doing this.

Commercial properties come with potentially several different pitfalls that residential properties do not.

Do some research on Section 8 to get an understanding of how it works, possible pitfalls, etc.

Planning to house hack a "plex " and keep current SFH and turn it into a rental. Other than looking at my mortgage to make sure the bank doesn't have a "must be owner occupied " clause , and getting rental insurance w...

What are the pitfalls of a partial interest property ?  

Example:

Property: 3 quadruplex buildings on the same street with separate mortgages owned by the same owner.

Sale price: 1,100,000 with buyer putting 15% down.
Owner provides a WRAP of 935,000 at a 5.5% fixed rate...

Just found this:http://rejournalonline.com/a-tax-lien-pitfall-you-must-factor-in-when-planning-your-tax-deed-investment-strategy/853339/...