I trust she will provide an update once the dust settles from the tax reform.

According to the tax professional in this thread, you don't need a LLC to get the 20% deduction: Tax reform Q&A Thread 1 - Pass-through and 20% deduction.

I know there have been recent changes with the tax reform, so my question is whether I should go ahead and form an LLC, some other type of business entity, or keep everything in my name?

Implementing strategies for tax free moves is huge and particularly in CA where taxes on investing were onerous, are now made worse with the tax reform bill, and follow you even if you take your investment real estate outside CA.So given my proclivity for tax advantage I'd look at your situation and say you need to sell asset B while you can still take advantage of the primary residence exclusion. 

I was just reading an article on BP that stated the new tax reform would not let me write off the Refi interest.

(Referring to the new tax reform)Good Luck! 

Not sure if any one this content helps but the real question here is how I should structure my business, considering the recent tax reform as well as my intent to only deal in buy and hold properties. 

@Carter BushmanThe classic strategy of reducing SE taxes (Social Security and Medicare) by restructuring as an S-corp and starting to pay yourself W2 salary, as implied by @Daniel Hyman, is significantly undermined by the new tax reform.

If your second home vacation rental is on schedule E as I've been told it should be then everything is still deductible as before.Plus there is the 20% deduction from business income in addition.I just listened to a Tax attorney on a 2 hour call yesterday and the tax reform is a great thing for real Estate investors.

Imagine moving into a rental that has a boarded up house on your left and right.I do believe in the long term (or even short term) appreciation of East Franklinton if the city actually executes its plans on reforming it.