Do you think it would work to just swap out the glass with the solid material structurally (e.g. held in place by the frame)? 

Try to get the same pattern or color of linens, that way sheets and pillow covers can be swapped. 

My only hypothetical solve would be to swap our payment processor 1099 into her name for the year prior to applying for loans so she has that income.  

Maybe you, me and @Mark Jones get together sometime and swap stories.

In San Diego, you need a permit to swap water heaters (never seen it enforced).

For example, swapping off the lights if the tenants pay electricity wow, nice to be energy efficient does not provide any value to use the owner.

I’m sure we could swap stories about burns, because I’ve had my share from investors, just like you’ve had from a realtor.  

So you can continuously "swap till you drop" slightly less morbid than @Clayton Mobley's line- although the same strategy. 

I would also swap out old light fixtures if necessary.

I'd imagine that the issues you're having with the current 8 unit would only be amplified when swapping up for a 43 unit in a worse location that needs significant work.I think your idea is the natural progression of a buy and hold cash flowing strategy and seems like it could be a great move, but the right systems have to be in place for this to work like you want.