Hi pilgrim,

1) Unless I know the loads and required stiffness, I would use a symetrical sandwich (i.e. 0/+-45/90 inside and outside) with the most fibres in direction of the main loads (from stern to bow?) but not too far from 30%/40%/30%.
If I understand you right, you want to use 200g inside and 200g outside, and midships reinforced by another 200g + 200g? Sounds a bit oversized. I would locate the areas where you need reinforcement (i.e. between the beams, along the keel, where you put the feets for trapezing and righting, around any force introduction. You can use glass instead of kevlar for insulation, does the same as good as the other.
2) yes, timber or large radius CFRP L. It needs to be strong, hence no foam. It will add so much integrity and durability for so less weight.
3) Sandwich would be enough. Add a bulkhead under the attachement for the bridle wires as well
4) I would do epoxy plugs around the bold holes, but hardwood is also possible if protected from moisture.
5) Possible, but I would prefer metal, because it will not break, just bend, if hit. And so far I bend this on all my boats...
6) if you sail single hand: symetric, if you sail dh, you could have asymteric ones. But the boards must be slightly larger, since only one is in the water. Profile and thickness are much more important than aspect ratio, area is more important than aspect ratio. A too small board with high aspect ratio will be a bad performer. DH needs more board area than SH. You can contact me for profiles better than std NACA sections.
7) yes
8) no, but you could have and reduce the weight of the carbon clothes of the sandwich skins.

Ok some words of my background:
I am an engineer with degree in aviation and working for a larger airframe builder for preliminary aircraft design, so I am neither an expert for CFRP nor manufacturing. I have never build a boat, but some parts and repair jobs. Hence be sceptical with my input.

Cheers,

Klaus