Or property taxes don't double sometimes? 

But licensing,zoning,insuring, owning and operating one are a different story.This is what my initial plan is (This is all in theory) To enter a new buyer program to purchase our first home using both of our tax return dollars.

One of the greatest benefits to the Philadelphia market is the low property tax.

If it was a gift he’d inherit her cost basis and owe capital gains tax upon sale that would have disappeared at her passing.

It has something to do with reducing self-employment taxes of 15.3%.LLCs are generally used for passive income like buy-and-hold investments. ...

However, it turns out that the seller's LLC was unregistered as they had not paid their property tax on time.

Primary residences are different than typical rentals for 'asset protection'.Your state may have homestead protections you may forego and/or you may not qualify for cap gain tax exclusion at sale by not owning as a natural person.Private money terms are likely your biggest asset risk, not fear of lawsuits. 

Would I still be allowed to deduct interests from my personal tax returns?

Double lot = 2x property taxes.

Unfortunately, property taxes and HOA fees have also risen, while rental rates for the property have not kept up.