Greetings from Toronto, Canada!

I recently submitted an idea to a sculpture festival, and they've accepted my proposal. 
Now I have 3 months to build and install it (totally self funded as well).
The following is a quick overview of my experience and tools.
If any of you offer advice I'd be most grateful.

Current Experience and Tool Access:
- have a high rez 3D scan file of a Toy Giraffe
- have been doing small layer CNC carving on an X-Carve from 3D tool paths generated in Fusion 360
- have basic knowledge of silicone mold making and small casts (from previous projects)
- have very basic understanding of basic layup process, and some of the differences between epoxy and polyester

Tentative Approach:
- cutting many (84) layers on the CNC mill out of foam, basic finishing
- EITHER building up layers of fiberglass on top of the foam (with tinfoil layer if polyester) or making a number of larger molds and doing layup into the molds.
- the fear is with adding material on top of the mill work, I will lose most of the detail if it is to be strong enough. Making molds on the other hand adds many more steps and material investment (silicone, mother molds etc)

Seeking Advice on:
- how many layers of what kind of fiberglass and resin I will need to make it strong enough that it will be OK if people climb on it?
- any suggestions on epoxy vs polyester? Polyester is appealing for my budget, and also because it will be ouside for 4 months (I've read the epoxy doesn't like the sun).
- any other general approaches.

p.s. I have access to a space where I can leave work to cure for weeks on end (regarding polyester fumes) but it isn't consistently heated and Canada is pretty cold in winter.


MUCH MUCH thanks for any direction or suggestions on my approach, what I might be missing, or what I should be researching.

No, not like delamination. Fisheyeing ruins your surface, because the resin doesn't stay flat. Google it for pictures, than you will understand. Where did I mention delamination? I guess you meant my opinion to the tinfoil barrier? My concern here is, that the core isn't bonded to the tinfoil, and therefore the core isn't bonded to the laminate either. That way, the foam doesn't act like a sandwichcore, wich would be beneficial for your application (sandwich= good).
If you use epoxy, you don't need a forced ventilation, but a stable room temperature. If you are working with polyester,  you'll need good ventilation, but temperatures could be lower, to a certain degree.
Are you aware, that this would be a really expensive project? you should definitely try to build something smaller with the same techniques, to get a feeling for that kind of work. Especially when working with epoxy.