It all depends on your risk tolerance and if cash flow supports it. 

You should look into Series-LLC and see if that's an option for you - then you don't need to worry about this question, as you can place a property in its own children Series-LLC that you can form when needed.As for distribution, you can have one or more per LLC, and that depends on multiple factors:- property class - you might not want to mix A class property with a D class property in the same LLC, due to different tenant level- cash flow - you might want to keep your cash flow cow separate from the ones that barely produce- equity - you might want to keep the one with large equity in its own LLC while you can group the ones with little equity in another LLC (let's say you have one with 50K equity in its own LLC and 3 other each with only 10K in another LLC, till their equity grows to your risk threshold when you move them out in their own LLC).- number of units (in the case of MF)- location of real estateThe investor has to decide what mix is optimal for their situation.

The right realtor will be a resource for you, but under no circumstances should you be dependent on them.

It just depends on your goals and how much you have to work with.  

What you will pay in interest on the "rehab" fund depends upon your network of private lenders. 

Typically, it will require 30-50% down (depending on the lender you use, property type, state and few other factors).

You're completely dependent on the quality of your property management company and when they do a poor job screening, you end up with a destroyed property and expensive evictions.

But you can only use non-recourse financing, which typically requires larger down-payment, depending on the balance of your 401k and the purchase price, this may or may not work for you.

Depends on what you want and what kind of connections you have.

To reiterate, a lot depends on the overall returns.