Has anyone ever come across this situation?  

Here is our situation.

The houses are literally next door to each other which is somewhat of an odd coincidence, but I'm now in a situation after completing a full rehab on the property I purchased and finalizing on a BRRRR that I can devote a bunch of effort into trying to obtain the unit next door. 

I don't know who you would call in that situation, but I would definitely call someone before allowing anyone onto the property.

Inventory is low (less than 2 months for residential houses) and there are still multiples offer situations on well priced properties. 

It depends on the situation, but yes if you are making offers low enough that 90% of them will not be in contention, and you are asking for bids on every one contractors will get fed up with you real fast. 

And if so, how does that work in this situation? 

On the podcasts, the term refinance is used frequently but I am not sure how it applies to this situation.

Of course, there are exceptions to the rules below and every situation will look different at every turn.

For what properties and situations it is most useful.