We all have been in a situation where we were mad and wanted to screw the person we were angry at.

Do a "take off" of the materials you think you need (think drywall, take SF of the walls, ceilings, etc. and determine how many you need, how much compound, tape, corners, screws, etc...) and do the math.

I'll re-evaluate my numbers as practicing definitely helps point out flaws in early assumptions.I think my biggest concern (beyond just getting myself into a money pit) is that somehow I'd be inadvertently screwing over someone who's a genuine friend.

Screws through the window sashes.  

This could be a huge place for lots of value addSecond thing to think about - if you're thinking of paying someone, get on youtube, give whatever it is a try, and if you screw it up, you're right back to where you started - having to call someone, but if you do it right, then you're money ahead.  

Another way of saying that, I would consider any source of income that rises and falls on its own, and that requires separate expertise, as a separate source - the whole point of having multiple streams is so you can screw up with one and still keep chugging along (?).

Screwing sellers out of thousands of dollars and acting as an agent by skirting laws has no value.

If it's new and no sale the previous borrower will have some say if they had no knowledge of the screw up and can show reasonably they never intended to grant two houses on one loan program.

There's more too this bank they are screwing around on other things..

I'll give you an example of a deal I screwed up and didn't complete from an landlord who's renter stopped paying, she lost the house.