Tina has a twin brother named Bobby, who she supplies with Jet to feed his addiction. She admits that it was she herself who caused him to become an addict, but she is also eager to help him get clean, and so seeks help from the Sole Survivor. She is also rumored to be having an affair with Holt Combes, father of Erin.
Tina is meant to be optionally recruited as a tier 4 merchant at the end of Dependency, but due to a larger bug with traders she may not be successfully recruited unless Bobby De Luca is dead. If asked, she may initially agree only to immediately express confusion at the idea; even if she agrees, the workshop assignment menu will not come up, keeping her stuck in Vault 81 indefinitely. Activation of this bug will also cause Dependency to become bugged, with the objective 'Talk to Tina' impossible to complete. Instead, you will have to talk to Rachel. Upon doing so the quest will be completed. [verified] There is a chance the game will say it's unable to save, telling you to get rid of 0KB, while the save created will appear to be there, but goes to the last save point before asking Tina to work for you.
This issue can be avoided by insulting Bobby, using the speech options on the right, then killing him when he attacks. Speaking with Tina again, and passing the Charisma check, will allow her to be recruited to a settlement.
She can still be recruited if Bobby De Luca was not killed during the quest Dependency. Use the console commandresetquest V81_03 and then setstage V81_03 100 to restart the quest, and then kill him.
There is a chance that the mission will complete even though Tina herself is unsure about leaving the vault.
Sometimes after successfully being recruited and sent to one of the available settlements, Tina De Luca may not show up at the settlement where she is being sent to. [verified]
One way to ensure her going to the settlement is by following her from Vault 81 to the assigned settlement. Other methods could also be applied in this case like using console commands.
It helps to send her to a healthy settlement with a Level 4 trading store already installed.
After Tina moves to one of the player's settlements she will stop talking. This is because she does not have any settler dialogue unless she is moved to Vault 88, but even then she will just repeat the dialogue she says when leaving Vault 81. [verified]