For my two bobs worth, the bilge pump(s) should not go through the main panel. It should be on a fused circuit of its own.
It should be wired directly to a main battery
with as water
tight connections as possible.
It should definately NOT have any relays. Each pump should have a Auto/manual/and off switch.
The choice of alerting devices is up to you , but rember a light that cant be seen is a trap, in the same way that an audible alert that cant be heard is a trap. The position of a light is critical. Can you see it from all positions . An audible alarm that is drowned out by engine noise
or the noise
of a storm is equally a problem.
Further. For every device that you add to this critical piece of equipment
you are lessening its reliability
. I am not saying dont have warnings, but I am saying think very carefully of their purpose and location.
The bloody thing better work in the dark with all other systems out in the worst possible scenario.....
If you need to have complications, then go for it...BUT install a "last man standing" bilge pump that has none as well.
If you think that a manual one will compensate...try yours for half an hour with a hose running into the bilge....I think that you will find that the joy of an electrical one running while you run around trying to stem the inflow is worth it. : )