Yes, that's essentially the process except for one thing. The harness also connects to the TCC solenoid. So you'll have to unsnap it from all the solenoids first, replace the TCC solenoid, and then install the new harness.
And yes, that's where the harness connects, but also if you look closely there is another square connector on the TCC solenoid and there will be a third pressure regulating solenoid that isn't shown in that picture that it unsnaps from. The harness goes completely across the valve body, connecting to all three solenoids and then out through a hole in the top of the tranny on the passenger side.
Also, I'm not sure how replacing the fuel filter is related lol... (nvm, post removed, I guess the guy was spamming...)