...The only thing future wise that I can think of would be the fitting of a stay alive and that would be only if the Loco needs one for uninterrupted running , do any of these wires need to remain for that ? .
Unlikely. The common ground connection is on one of the six pins if memory serves, and the other connection is probably somewhere on the decoder board, there may be a solder pad if you are lucky! (I'd suggest researching that before purchase, and I see you have just spotted another 'trap'!)
Then again, you may find as I do that 'stay alive' is never required. I was greatly attracted to this feature when first looking at DCC (now twenty years ago!) and bought the Lenz UPS unit to try with the then very new Gold decoders. Oh boy did it work, but how often did I want to put a sheet of paper on the tracks and see the loco continue to run under full control? On a properly wired, live crossing point, all metal wheeled stock layout, in regular operation, it was simply unnecessary.
The constant DCC track power at whatever 'full voltage' is set (I have my system set to deliver 15V at the motor terminals) 'gets through', operation is near completely reliable without stay alive assistance, and it gets better
. When I see the occasional loss of reliability, which is the moment when a loco 'stutters' slightly at dead slow, that is diagnostic of some dirt having arrived on the loco wheels or railhead. Immediate action to clean up keeps the layout clean. I wouldn't want that 'stutter' masked by a stay alive, it's a clear signal that a gob of dirt has fallen off a loco onto the rail and should be dealt with.