Breaker trips after attempting to install a new outlet
Are you saying that you were changing outlets when they were hot? Or simply that the last outlet sparked? If the latter, it could be a defective outlet or defective install. And it's possible that the sparking incident damaged a previously functional outlet. Don't re-install something that's charred. Look closely again for nicks in the insulation.

I'd try again with a new receptacle, but leave the outlet hanging out of the junction box temporarily and see what happens. If that works, then turn off the power, mount the receptacle and see what happens.

It should go without saying that all circuits should be off when you're working on them.