In the meantime, I'll knock out a few hundred sales calls between now and then 

Owner occupied will knock out quite a few private lenders.  

It's tempting to use a hard money lender and knock out a huge sweeping reno right up front, cash-out refinance, then pay back the lender.

To be honest I don’t knowI have always looked in awe at the flip TV shows and thought wow that must be expensive to knock out a 10 or 15’ wall.  

My opinion honestly is that if your in a single family neighborhood and you try to turn it more Into a duplex the neighborhood HOA won't allow it and to have two separate units in one building you'd probably need to knock out walls and add a divider in the middle for privacy, which is going to cost you more money.

If the buildings are older, you may have more expenses due to the age of the asset, which could potentially knock out the cash flow even if it is a higher cash flow due to a lower purchase price.  

This all needs some investigation.I see a few options, in two main veins:Piecemeal replacement:1) Jack a section from the inside by attaching a support beam to the studs and take enough pressure off the structure to knock out all the rotten wood, cut and sister the bad studs and put in pressure treated lumber.

It's all about the strategies and processes of being a landlord and getting things into order, it seems like it would help you knock out some of those tasks and tells you very smart ways to go about them. 

If you want to make the kitchen bigger - is it possible, and worth it - to knock out a wall and put in an island?

I would probably get a grout removal tool, but just crape it through to knock out any loose or bad grout.