The CZ or a Howa or any bolt action with a suppressor will fit the bill nicely. For a big Bomb up the Howa short actions (308, 243, 223) can be fitted with a 10 shot mag but if you go semi, the law says you are only allowed 7. Bolt action will be quieter. A lever action 30/30 would also do but they are either long mags or suppressed. You cannot do both with those.
As for the walking stick function, get some shooting sticks. Safer and they can be used provide stability for longer shots. I would never use a rifle as a walking stick, especially not a semi auto.
