There are a few good books although not many pertaining to this niche of real estate investing.

I wanted to know what you all think about the 70% rule as it pertains to flipping houses.How do you feel about it in this current market?

I dont *think* those things pertain if you 'borrow' from your SOLO401K, but I'll let others clarify that. 

The name dropped in that context wont be one riddled with overlays pertaining to rental income.

My question pertains to your third post.

AirBNB specifically recommends language pertaining to allergies and service animals - you can state in your listing that you don't accept any animals (don't say "pets") due to allergies and it being a health risk to you or a family member.Again, definitely look into the laws yourself, but between this being your primary residence, your only STR, and you having allergies, I don't believe you could be required to accommodate service animals.

If you have investors, the Operating Agreement should spell out many issues pertaining to the ownership and operation of the LLC.I do NOT recommend trying to cut corners on your LLC. 

A lot of the time, factors pertaining to a property willdetermine what carrier an agent can get you covered under or not.

I believe it's a contract pertaining to the lease of real estate for more than 1 year has to be in writing.See:https://statutes.capitol.texas.gov/Docs/BC/htm/BC.26.htm

However as your questions pertains to ethics being a realtor/investor, I would say no you should be fine.