A-322 is looking good! I'm get the idea that she'll be well taken care of... Don't worry too much about this being your first sailboat - the way these boats sail - you'll be hooked soon enough! It does not hurt to plan ahead...

Regarding the motor; It seems like you're headed towards repowering with an inboard diesel... If you do not have tides & currents to worry about; I'd say pull the seized A-4 out and use a small outboard (2-3 hp) to get you by. (You can always add some ballast to trim as needed) This will get you out in the water and you can look around to see what options are available. (e.g - if any other motors have similar mounts) in the meantime.

Refurbished A4s come up for sale ocasionally...

Oh - the bulbs are 12v. At least in most A/Cs I've run into.