Place AIs at the base near Villeneuve
Take them into your group, order them to follow you, and then get into the vehicle.

It is possible that the players in the group interfered or maybe the previous squad leader already had bots and they tried to line up in one formation

Workaround:
Kick bots out of the old squad.
Create a new one.
Add bots to it.
Now they obey your orders.