Residential contract aren't that complicated and do a few deals you can already know all the clauses in it. 

Things get even more complicated when you have multiple rentals and you end up having to use class tracking to try to keep them separate. 

This can get complicated if you are racing against time between getting it sold versus the banks take over.Can you get it sold at a high enough price to pay off the mortgage or is the owner under water?

I think you're making this more complicated than it has to be.

They are one LLC and you’ve defeated the purpose if there was one other than complicating your life. 

I think its too complicated to make sure you are always using the right card and bank account for the right property portion.

This is overly complicated, but I see why you're doing it. 

I was just in the hospital with complications with my pregnancy, and am pretty overwhelmed with dealing with that.

This gets complicated and we have to optimize the  FICA/SE tax-saving vs income tax saving via retirement contribution. 

Insert a rollover clause for an additional year in case you need a bit more time to get financing.The lease should not mention the option, and the option should not mention the lease--if things go sideways, you'll be able to part ways with fewer complications.