1983 23' thruhull and plumbing for live well

[buellie21]

I have an '83 23' with the below deck livewell in the stern. I'm getting ready to put a thruhull in so I can install a pump to feed the live well and also plumb a washdown pump. The live well currently has no feed only a drain out the transom. Looking for some wisdom here; ie. where to place the thruhull, what size, pickup or no pickup, what size pump to keep stuff alive here in FL?

Also, does washdown pump need to be below waterline or can i put it above deck in the rear corner storage compartment, etc.

Any ideas or thoughs would be greatly appreciated. DB