@Jermaine WhitePretty much what you already have access to on most websites.The MLS will sometimes have better search functions, but that depends on which MLS you are using.

Depends on the type of encroachment.

General rule (for more reasons than one):Buy and hold rentals=LLC or hold in your personal nameFlipping=S-Corp (although this depends on some other factors as well such as your total profit and W-2 income) It may not be worth it depending on your situation.

If they are interested in terminating the rental contract for $$, there's no issue I can see.A lawyer is your best source of info so call one and pay the $50 for the 5 minutes to be certain if you're going to lose sleep over it.But beyond that, if you are depending on the 3 units rental income to make your payments while you rehab one at a time, then it makes more sense to remove one at a time.  

For example a fourplex; one tenant moves out at end of his/her lease, now you can go in there, revamp the place and raise the rent for the next tenant (obviously depending on market demands and similar rents in the area.)

Appraisers generally are looking at rents and square footage when selecting comps depending on the type of property.

It all depends on the market.Don't be afraid (if you like the agent) to ask for fixed up sold comps.

But it all depends what you're comfortable with, and if you're investing in Class A, B, or C neighborhoods. 

The ability to pull your money back out after the refi is largely (or solely) dependent upon the forced equity you create.

It depends on what your policy states.Most of my clients who have had total losses(max policy payout) will get paid directly and general contract the rehab or sell as is.