What would you pass along to a fellow investor during the scale up? 

The quote is to get a number obviously but also kind of an interview for you to judge their integrity and character.I like to find guys who are kind of on my level - have some experience but working on scaling up.

This would actually be a great opportunity to sell the duplex...and buy a large apartment building since you have so much equity and they tend to produce better income . 

I would say that range is too large to get any accuracy in your valuation. 

Sorry to not be full of good news, but I would try to scale back the reno as much as possible.

Considering possible interior and exterior damage from the large dog of the remaining tenants, and other damage that may not become evident until prepping house for next tenant, how can we handle the refund of security deposit to MIL couple, since, per the text of the lease: “All Lessees are jointly, severally and individually bound by, and liable under, the terms and conditions of this Lease.”?

The big markets from state to state are largely very similar.  

I worked at a large company closing a division that had sizable receivable on the books, and the company gave me full authority to settle it.

I just can't believe how easy this has been on such a small scale.

It has only been on the market for 30days, but the sellers were overzealous and decided to go put down a very LARGE deposit on a "to-be-built" house.