I would also like to replace my existing manual bilge pump hose, but it was put in place before the liner was installed and will not budge. I'd be surprised if yours was easy to remove. My plan is to run a second smaller hose beside the manual hose for an electric pump in the main bilge, which requires holes in the 2 beams under the sole. As far as the engine bilge I am installing a small electric Whale pump there without a float switch, just a switch that is momentary on one side and the other side is manual on. This will prevent pumping oil automatically.
I would stay away from portable solutions and valves as much as possible. You say a small leak is not a problem - if on the suction side the leak will cause problems.
Living aboard in Victoria Harbour