According to terminals in the Vault they were working alongside Mariposa actually.

http://fallout.gamepedia.com/Vault_87_terminal_entries#Entry_87-34190

"The latest subjects in the Evolutionary Experimentation Program (EEP) are showing some promise after only a single exposure to the modified FEV. We are currently testing five subjects, two males and three females. Each one of them is under 24 hour observation as usual. We hope to have a breakthrough in this strain as the continual pressure from Vault-Tec and the military at Mariposa is becoming most bothersome."

This is hilarious.

doesnt matter what beth does if its lore friendly or not there will always be complainers I say let the developers do there thing and Ill do my thing play!