A buddy of mine suggested I change the oil once it reaches operating temps just to get all the assembly lube flushed out and get some fresh oil back in it for the break-in. I never did that before but I figured what the hell, it definitely won't hurt to have fresher oil in it.#1. And why are we changing the oil after start up? Unless you have contaminated the oil in some way w/ gas, or water/antifreeze,....leave it in there at least for the initial break-in (If it's a new motor).
#2. Buy a test light. They're cheap, and will tell you instantly which circuit is hot.
#3. as for which fuse,...I'm not the one to ask. I don't have a stock, (and haven't had ) a stock fuse panel on a Mustang since '12.

The last time I was searching trying to figure out why I couldn't start the car we were trying to figure out why the fuel pump wouldn't get power from the "key on" position and we came up empty. The only thing we didn't check was the inertia switch. I'll check that next time and go down the checklist @jrichker just posted.
Anyway, we finally gave up on that and just used a screwdriver on the solenoid on the starter to start it up. But between trying to find that sweet-spot with the distributor and holding the throttle we just never got it to idle. Then the belt started to fray because I must not have reinstalled the power steering pulley all the way on because it caused the belt to walk. I'm uploading one of the many videos of the car running.... not for long , but running. Sound quality isn't great because it was recorded with my phone(Galaxy S6 Edge+). I'll post it when its finished uploading to YouTube.

eating grin says it all. That's why we do this. 
