Silencing is easy. Use 15mm copper pipe and calm the exhaust gasses. Then shove it into as big an expansion box as you can get in and use a 3/16" final exhaust pipe.
I used mine in a Suburban N London garden and nobody complained so I think exhaust levels are objective.
If OS have withdrawn the pull start version use a big generator and use it also as a starter. I did that on my first loco, the Pilgrim Pioneer. I bought a car relay unit to start it as the current load is big. An onboard 12V battery pack is enough to turn the engine.
Anyway I have done it all this way and will do one more in a year or three. There are more ways than one to make these work.
Best of success.