Ruckus' average position relies on what legendary card he picks. If he has Recycler, he'll often be to the side of the objective, if he has Flux Generator he'll usually be on the objective. If he has Aerial Assault he may be above your team.
Frontliners Tip
Use your "CC reduction" card + "Resilience" to deny point pressure from "Grumpy Bomb".
BK feels relatively safe you while stunned. "Jumping out" of stun earlier, works like surprise effect & confuses him.
Pay attention for his "Poppy Bomb" usage. If you see BK landing with low or even half HP - try to pressure him. BK can't use his escape for next 6-8 second, that would be enough time to kill him.