I would also add the second fin. I don't have it and after talking to several Axis owners, I wish I did have it.
I would get:
minimum 350 engine
at least one set of swivel racks. They aren't that much more expensive and are great racks. You'll definitely want the boards out of the way with three kids!
the tower mounted rear view mirror
second fin
wedge
surf gate
interior LEDs for inside compartments
additional rear and front ballast
I'm sure theres others but these come to mind as musts for me
Forget the Z5 bimini top. You don't need it, and the factory one is just fine (if you want to stay $70k or below.. Its expensive!)
Get the stereo pack three I guess, but it'll drive your price way up. There is lots of good stereo stuff on the market and you way want to contact
a good local marine stereo place and see what the difference would cost. You gotta have a nice stereo with a nice boat!