We are one property at a time lenders and PA is a high closing cost state which would make it cost-prohibitive to keep refinancing".

You also might want to check out Florida Statute 83.67 for Prohibited Practices - Prohibited PracticesBest of luck with your newest investment property and the new learning experience! 

As you mention, even if you prohibit pets, some may sneak them in.

Yes, but you need to narrow it down a lot to have a coherent answer.You will have to look at (I'd recommend in this order) the city codes (if it's inside a city, many cities above 50-100k population aren't friendly to development of these), the county codes (most counties are friendly to these, but you will probably have significant issues in major counties like Bexar, Travis, Dallas, Denton, Tarrant, Harris, etc), then you will have to comply with the state-level (TCEQ and others) on the water supply and waste water treatment systems.To put it in perspective again, in say Dallas or Austin, you will likely have prohibitions or very significant hurdles on developing RV or tiny home properties even on unincorporated, "unrestricted," AG-zoned properties at both the city/municipal level and county level.

Here's the cheat sheet of what you CAN'T prohibit/favor/disfavor, etc. 

I don't know if your state has a prohibition against that.

If I start a legal entity to buy my first home can I still use the loans or are there legalities that prohibit that?

That means you can prohibit kids or animals if they are pets or emotional support (service animals are under ADA, so you would not be able to deny).

I'm  also pretty sure there are rules on BP prohibiting me from explaining my actual thoughts right now. 

If you are doing that work personally, that could be viewed as providing services to your plan and a prohibited transaction.2) An IRA is tax exempt when receiving passive income such as interest, dividends, rents from real property, etc.