Regular Outlet Tripped, Now Various Outlets Are Dead
Another backstab casualty

We get these all the time.  

First, the arc flash when you opened up the first box had a simple reason: the receptacle shifted position, and the "hot" screws on the side of the receptacle hit the grounded metal box.  Possibly contributing was the screws being all the way out in their highest position, because the screws were not used to attach the wires.  This surge was massive, in the hundreds of amps, and it caused the root problem.  

The root problem is most likely one we've seen before: "backstab" connections in receptacles upstream of the incident socket.  Backstabs are intended for high production assembly of house wiring e.g. In developments.  The "electrician" jabs the wires in a hole, and the hole grabs the wire. However, these make "point" contact with the wire in just 2 places, quite unlike the long edge contact you get on a side screw.  As such, they are very vulnerable to "failing open" under heavy load, even when loaded only with ordinary household loads such as a 12A heater. 

This is made much worse when a wire is pried out of a backstab, and the hole reused; extracting the first wire weakens the spring.  It is, after all, only 1 of 4 springs in a 60 cent socket.  I've seen backstabs designed to make edge contact, but they respond badly to side strain on the wire, and it's hard to avoid that when shoving wires into the junction box.

The upshot is, I bet you will find a lot of backstabs in this house.  If you knew the circuit layout, you could focus on the first failed outlet and the one before.

Twist/pull the wires out of the backstabs, don't cut them because a) it's a waste of precious wire length, and b) you can then inspect the wires for evidence of arcing. Move them to the side screws, and torque firmly (Code now calls for a torque screwdriver).  Also run down all the side screws.  Bonus points for wrapping the outlet a few turns of electrical tape to cover all the screws.  Don't back screws all the way off, that wrecks the receptacle.