Both have been fantastic and I’d recommend them as great resources to both, answer questions AND generate new ones!

Properly structured, even in a catastrophic loss they will still provide some shielding of your personal assets.Second, it provides tax advantages not otherwise available to an investor.The general approach is to "control everything, own nothing".

II feel Union City is the one with most advantages for its NY proximity, 3 Bedroom can easily be rented for $2K per month, however bnie mindful of rent control recently put into effect.

Unless you invest via an LLC owned by the IRA, you will not have checkbook control over the funds which means you need to run transactions (e.g. income, expenses, etc.) through the trust company who will need time to process the transactions and generally charge fees for each transaction.

Some others like the "control". 

If I find a fantastic opportunity, I will either have enough to take it down myself or I will need a partner.

The process is just far less standardized and controlled relative to traditional transactions so you really have to pay attention to every detail and make sure everything is verified. 

I believe you can purchase an Airbnb property using a vacation/second home mortgage with 10% down as long as you have control.  

Select your partners wisely - Realtor, Lender, 203k Consultant, and ContractorREALTOR - it's recommended to work with one that has done a 203k in the past so they know what verbiage HUD wants to be added to the purchase offer contract and how to structure the dealLender - advice you to select a lender with verified 203k experience; the lender is the quarterback in the process, controlling the rules, paperwork, processes, procedures, and if the lender does not have sufficient experience with the 203k, your entire process can look like the Cleveland Browns on a Sunday afternoon203k Consultant - the lender is responsible for selecting the 203k Consultant (refer to Lender paragraph above); this person determines the scope of work and pricing for the projectContractor - strongly advise you to select a Certified 203k Contractor; this person does not set the pricing (see 203k Consultant info above) but does need to know the different versions of the 203k, payment methods, timelines, paperwork, and processes; definitely don't want to work with a contractor who is going to "wing it" on a 203k.

Those are fantastic numbers!