May want to have pictures with a date and time stamp.

As a mason I install stamped concrete overlays on structurally sound concrete all the time.

They do all sorts of funny things, to the point that I once spoke with someone identifying themselves as a B of A employee that, according to who stamps the back of the mortgage payment check, was most certainly NOT a BofA employee and the branding on the bill was Citibank anyways so someone obviously had the wrong script open in any case, but who stamps the back of the check is Nationstar....

Especially very small businesses, so don't be blinded by their shiny trucks and colorful shirts.

Note his head scarf, neck/face scarf and long sleeve shirts. 

They will tell you what drawings, engineering, inspections, etc that you will need throughout the process.You will likely need stamped engineered drawings for taking out the wall.

I guess my main question is...as a newbie...am I building in too much extra for into the "oh crap I really screwed this up and I'm totally going to lose my shirt" fund?

I wouldn't let him do any work if he cant stamp permits.

I know the feeling as you are overly anxious to get started with the renovations.In my mind's eye I see your grand plan unfold, as you get ready to upgrade this flat to bear your stamp of approval.I/we look forward to the pre and post photos.Good luck on your REI journey!

"The times will impact all deals all the time depending on the times"That would make a great shirt man!