Many houses I show up and start taking photos of work done by contractors and send it to the owners including: bad drywall repairs, crooked cabinets, chipped counters, holes left in roofs, lights that don't work, loose toilets, baseboards never painted, drips and runs in paint,  cabinets never sanded (rough to touch look ok in photos) tile floors uneven, the list simply goes on and on. 

Again, this can range from easy (cutting a hole in an exterior wall with wood frame construction) to much more difficult (block construction, multi-story or basement applications, for example). 

Also, I am looking into the sort term rental loop hole to lower my w2 taxes as well as BRRRR if I find some great deals.

This has the potential to go down a rabbit hole where they can ask for invoices for personal loan's utilization and if you alter those documents, you WOULD be committing mortgage fraud

On a properly purchased and efficiently managed unit, cash flow should go up and up and up... if you start from zero and spend the first years digging out of the hole, going up is a much harder thing to do.

It is not that the expense is non-recurring - you would hope that you don't have to continually fix holes in the wall. 

You can also do test holes in the sheetrock if you have a camera to look inside it.Opening the wall is cheap though with drywall and paint and patch to fix so might want to go that route the first time.No legal advice.

The upstairs shower has a hole in the tile wall and with the size of the hole and condition of the tile/grout throughout, my friend who is doing alot of my work said that it will be easiest/look better to just redo the whole upper part of the shower.

I have an endorsement for drainage backup, I’m more concerned that the policy was a standard home owners insurance and didn’t include the rental portion.

I think it's because the basement (concrete, cinder block) walls are in direct contact with the soil (newer homes usually have a barrier or membrane fastened to the outside walls, which keeps water away from the wall, and forces it down to the footings, where the weeping or drainage tile is located), which contains a fair amount of water.