As for how much the individual units would rent for, you'll have to do a bit of research but here's an article I wrote with some resources you can use to get a pretty good idea: How to Determine Fair Market Rent.Hope that helps. 

The Air is pretty much worthless for just about everything.  

BTW I'm also the VP of a pretty big roofing company down here, so let me know if I can be of assistance,  I have a lot of connections in the contracting world.

These agencies have specific directives as government backed entities, one of which is to promote home ownership (as opposed to commercial lending).

I am pretty new to the REI scene myself.

There are several markets in the South and Midwest that are great for cash flow at much lower entry points than CA, but we're pretty excited about the future in Birmingham right now. 

The buyers plan on putting 20% down, seems like it should be pretty straight forward...

Pretty quickly

I don't think you want to syndicate as syndication costs can be pretty steep and won't be worth it for an 8-unit.

Looks like you've covered all the numbers pretty well.