Geeky student at the Art Institute of Portland. 3D desiger. Giant Star Wars/sci-fi nerd.
By and large the soldiers weren't humans - most of the humans were used for menial jobs like mining. The only example of in-universe humans that had much autonomy was a mining vessel captain under Sadow, and all the soldiers on board were still Massassi under a Kissai 'handler.'
The very reason there were probably a decent number of humans left over was because they weren't taken to battle. That and Vitiate (the future Sith Emperor) ended up sacrificing most of the powerful remaining Sith Lords in his immortality ritual. You can expect most of the Sith ground troops to be Massassi, who were bred specifically for the task and had no qualms about making their mark through violence.
(This is Calithlin by the way)
Kitty-Kitsune deserves major praise! :)
I'll answer to the best of my ability, but some things are certainly still in the air at this stage:
-If you mean the 'Sith Starfighter' from KOTOR, then no that will not likely appear in the mod, as it is actually a Republic design that Revan took the blueprints from and produced with the Star Forge. That design doesn't yet exist in 5,000 BBY. We will however have multiple starships for the Sith nonetheless.
-The Sith Meditation Sphere will definitely be present in the game. We hope to have many of the iconic vessels shown in the comics in the mod. We're still working out how it will function, but our early ideas have it being similar to the Death Star in that it may not actively participate in battles, but instead is a movable buff (battle meditation) that effects a large area of the galaxy (So it will be beneficial to have it positioned near the center of the map).
-The Republic has several types of ground troops we can derive unit types from, though fewer vehicles. We may need to bend the source material a bit or invent some plausible vehicles, but they will have comparable vehicles to match the Sith war beast units etc.
Hope that helps!