So, some interesting information regarding this Aves Apoxie product. I have contacted the company and done some research into the composition. Thanks to vivworks who has considerable insight into the chemical make up of many of these products my knowledge has grown, and now so will yours..hopefully.
with that, here is some info for people wanting to use it.
Aves Apoxie clay does not contain nonylphenol. I cannot get chemical composition data or structures from the company. nonylphenol is illegal in the UK, I confirmed Apoxie clay is sold there for the same purposes as here. The UK is particularly strict on things like this so I am confident it does not contain this compound.
Epoxy needs to be mixed properly in order to leave little or no unreacted material in the matrix. The only way to get near perfect ratios is by using a scale and weighing out each part in a 1:1 ratio. take it to 2 or 3 decimal places to be really accurate. Then spend a long time kneeing and mixing the clay till all color is uniform.
I have not looked into weather zoopoxy contains the substance but the prices are more and quantities are not very useful for small projects. also you have to pay for shipping Apoxie can be found at craft stores.
Apoxie has more available quantities, and colors and is cheaper than zoopoxy.
conclusion is, Apoxie is safe for aquariums, vivariums, terrariums. If mixed properly is essentially inert, and doesn not contain the compound nonylphenol.
I will start my build with the product soon! enjoy