Reactivating Rhonda requires a Science skill of 60. If the Courier reactivates Rhonda and leads it to Tabitha, they will complete the quest "Crazy, Crazy, Crazy", as Rhonda and Tabitha wander off together.
A peaceful resolution to the situation with Tabitha requires not letting three days of in-game time pass between the moment when first encountering Rhonda and the moment when trying to repair her. Rhonda will disappear from the game if her room is left and returned to in three days, due to her being set to never respawn.
Reactivating Rhonda and spending too long in the supply room will summon Tabitha and both will initiate combat.
After reuniting Rhonda and Tabitha, it is possible to sneak up to Rhonda and deactivate her with the Robotics Expert perk. Tabitha will then simply stand behind Rhonda and will still talk as if following her. Tabitha will not become hostile and there seems to be no way to reactivate Rhonda.
Rhonda becomes a temporary companion after reactivating her. However Tabitha will always talk to the Courier before they leave Black Mountain or even can engage in combat.