I've never heard him suggest that one way or another I would expose myself legally from under my LLC. 

Plumber is very expensive, and if they encounter/expose to any pipe that is not to code, they can make it very expensive.

Any debt financing will need to be non-recourse and the use of debt-financing will expose the IRA to nominal taxation on Unrelated Debt-Financed Income (UDFI).While the leverage is not as high as what you could achieve personally, the BRRR method of investing can be a great way to accelerate the growth of your IRA. 

You may still be exposed to civil liability risks, but it would make sense that you are more likely to be sued when you have 100 units than you would if you have 10, as you are far more exposed to liability with 100 people.Then again having more money by taking one more risk may insulate you financially a little bit.

From a legal standpoint, if you have any litigation taken against you that either exceeds your insurance OR your insurance refuses to cover... it leaves everything under your personal name's exposed.

Closing cost are things like title work, recording fees, reimbursement to seller for pre-paid items (taxes/oil/propane), etc.Closing cost should be lower on a seller finance deal as there are no banks involved.Your title company will be able to give you a close estimate, call and ask. 

Meaning, would the W&D be openly exposed in the room causing it to stand out in your rental photos or is it hidden by a closest or something?

In the event of a lawsuit by having it in your own name you will have exposed your personal assets to litigation.  

Are they doing everything they can to expose properties to the widest possible market?

Just hadn't been exposed to it prior.