If possible, mount electronics in a cooler, lower vibration environment. So the transom would be my preference.
With respect to the raw water pump. I can't tell where the bracket mounts- is it the block? This configuration means that the mass of the pump is hanging off the end of the crank, as that flat strapping won't support the pump body and in fact may add additional load. I would worry about fatigue failure from vibration.
I wonder if one from something like a 350 MAG MPI could be retrofit?
Or something like this, remote mounted:
https://daviescraig.com/category/ele...ater-pumps-ewp