A Lot of Thru-Hull Fittings

I was wondering if you veterans could take a look at all of these fitting and help me decide whether I should retain them ALL as I begin to enter the phase of my re-fit where I'm putting the boat back together.  It seems like most Contessa 26 boats I see photos of have very few if any fittings on the transom and this boat in comparison seems like it has A LOT of fittings. 

Here's is an explanation of the ones on the TRANSOM:
1. Upper left hole is for the diesel fuel tank vent
2. The small hole below and to the right of the fuel tank vent is the vent for the vacuum breaker associated with the engine sea water cooling system.
3. The upper big hole on the left is for the electric bilge pump outlet
4. The lower big hole on the left is the engine exhaust
5. The side decks drain through hoses connected to a tee that is on the inside of the big hole on the right
6. The red dots are the monitor windvane lower mounting bracket locations
7. The little holes on the centerline are for the upper rudder gudgeon

Explanation of the ones on the AFT HULL:
1. The drain at the top of the boot stripe on the starboard side is the manual bilge pump outlet
2. the two drains, right above the prop on each side, are for the cockpit drains and utilize crossed over hoses from left to right and vise versa.

Question examples:  Is it standard to run a hose all the way from the vacuum breaker on the cooling system to the transom?  Do the bilge pump drains seem to be well placed?  Is the big drain on the transom for the side decks a standard placement/good design?  etc.    thanks for reading!!!      ps -- I'm getting close to the end of my big question list