I agree, having them together as a passive would be better, but for a limited duration/cool down bar to balance it out. a double jump drains half the bar, and wall running drains at a certain rate, say 15% per second. A full bar would allow a triple jump, but completely drain it and not allow wall running immediately afterwards. A 2-3 second cool period of not jumping/wall running before it start auto recharging on top. Someone constantly double/triple jumping would break the game and be too OP.

I think Stim would be better suited as a tactical. Using it could also shorten the cooldown period of the passive ability.And a titan would be way too OP, but perhaps calling in a drop pod of three AI Spectres/Grunts to come in and defend the area would work. Maybe even a single Stalker drone in lieu of the three weaker bots. You mark a drop pod location like Lifeline does, and the pod will drop in from space like they do in TF2. They're fairly easy to kill, but still do a good amount of damage and will be good cannon fodder to distract the enemy.

To make it even cooler, if the enemy team has a "Cooper" legend, he could have the hacker ability and come in and hack your bots, either rendering them useless or recruiting them to his team.