For example, certain liens will not go away such as property tax liens, code enforcement liens, certain city liens, etc.  

If anyone has any advice or tips, please post them.

Also, will I continue to get the W-2 Tax benefits using the STR loophole if I move these properties into an LLC?

To some capital, as long as the product is not traditional vertical, apartment-style product then it is still build for rent.The biggest evolution I have seen in Build for rent recently is the transition to multi-parcel and for sale/for rent hybrid developments which is contrary to what was more standard in build for rent 5 years ago---traditional single parcel developments for density and tax purposes.

Any pitfalls to avoid or tips for making it a success?

This way you wouldn't need to provide paystubs, W-2s, tax returns etc. 

@Liam Bell"Rich Dad Poor Dad" and Gary Keller's book "The Millionaire Real Estate Investor" teach key tips for buying homes to make money.

If your LLC earns a profit on fees it earns from property management you will owe self-employment tax.

Can you take the small profit which may qualify as "tax free" and invest in properties on the mainland, or in a retirement account.

The same in Vegas Nevada has the 4th lowest property taxes that do not assess on the sale of the property, very different than CA.