I'm not sure how your Homeowner's Insurance will play into this.

It looks to have a promising future especially for those that can market it to the masses. - sophisticated value adds: development, TIC/coop, take advantage of localized regulations (2 off the top of my head: San Jose lot split for ADUs, San Diego city unlimited ADU count in existing conforming building), etc.  

I realize markets come into play but I would just like a general idea.

You can't go off of the cost estimate on permits and even beyond that, design, site work and a number of other factors will play a significant role in costs.

I had a rather complicated RE play I was doing in 2012 and of course financing was still non existent I sent a basic concept plan they looked at it for about 3 days and came back and said hey we like it just need 10k to move forward..

@Becca F.playing catch up is much better than never playing!

Its defiantly a good idea to do as much due diligence as you can on the seller if you are looking at doing a partial or a note fund.If it goes non-performing you need to make sure you can trust the person who will be responsible for getting the note re-performing and you need to understand the contract so you understand how the event of a non-performer should play out.I would definitely put Chris in the upper echelon of note investors based on my research and experience. 

This could play a role in which unit you decide to occupy. good luck 

It could be an easy fix like this or a bigger problem depending on the factors at play (are the joists accessible, will it mess anything else up if you just jack it up and reinforce, is there water damage or structural damage to the foundation causing the sag instead of just old joists, anything else going on like a supporting wall or posts under the floor, wiring or plumbing runs involved etc.).

When James moved into the master, he complained about Steve playing music too loud.