There are no mentions of the Gamorrean Stronghold, the only evidence of its existence are a few pre-release screenshots.
The Taris Undercity was developed very early on in development, it was at this stage in 2002 that a lot of the Kotor assets we know and take for granted simply weren't present. I theorize that Bioware came up with the Outcast Village, as it was better than whatever the Gamorrean Stronghold was going to be, and then moved the Gamorrean's into the sewers to have them be a foe there.
Here are some screenshots of the very early Outcast Village.
Gendar uses the generic fat commoner model found in the game files today (Furko Nelis and the Vulkar Sublevel Junkie use this appearance) with a head that ultimately didn't make it into the game. This head was either going to be a player head that got replaced with the PMHC01 head we have today, or it was going to be a commoner head as this same head is visible in other screenshots as Smuggler and Jedi Council Member appearances (Holdan incorrectly had a Jedi Council Member appearance in one of the screenshots but it used this head and the Smuggler appearance in the screenshots is the one Holdan uses today).
Rukil uses Jolee's appearance, I theorize that Jolee's appearance was made before Zelka Thorn's generic head as you can take Jolee and Zelka's head textures, overlay them in Photoshop, and see that Jolee's eyes are present on Zelka's head texture.
The Rakghouls in one of the screenshots are inside the Outcast village as the barriers to keep them inside the quarantine cage weren't implemented yet.
I theorize the droid you see in this screenshot is actually the same droid K1R restored in the Undercity, something I do wish to do at some point.
I have no plans to port anything from TOR for a restored content mod, another modder may wish to do this as a standalone mod but that isn't something I do.
It's custom content, and due to its age it'll probably won't be compatible with modern day mods. I "might" try to recreate this at some point, though it would be a separate mod to RC-K1CP.
Those will be added at some point.
Those will also be restored at some point, I can also say that I suspect it'll be easier to restore these two options than it'd be to restore the Outcast Children. Though that'll only mean that the Outcast Children will be added in an update after the Echani Merc and the Iriaz.
That is correct, you'll probably see the Echani Merc and Iriaz before the Sublevel... and I do hope we see the Outcast Children before the Sublevel too.