I was able to format the drive via the airport utility itself. Airport Utility might have improved in the 6 years since :D

I just installed a SEAGATE Exos 7E10 SATA 8TB 512e/4KN (ST8000NM017B), and the form factor is not the same as the original drive. The Exos is a lot "boxier." I had to hack quite a bit of the rubber to get it to fit. By the end, it was a bit of a squeeze and had to push it down to secure the bracket before screwing in the T8 screws. If I had more patience, I would have finessed the rubber a bit more.

+1 to needle technique, they both came out quite easily this way. I used bigger needles, specifically darning needles from this prym set. The smaller needles from the set were perfect, plus they have a nice taper so you can push in and gently begin to separate the connector, they kind of pop off a little. I've seen someone use needle nose tweezers, but it was too awkward for me, so I stuck with the needles.