Are traits the same as characteristics???

Traits are heritable through the genotype. Characteristics are the expression of the genotype into the phenotype; the effects of the environment.

For me it depends a little on who you are talking to - but in my area of biology (evolutionary ecology) the words are used fairly synonymously.

So for any individual in a population, I would say any particular phenotypic trait or characteristic value (which could be continuous e.g. body size, or categorial e.g., hair colour) can be determined by either genes or environmental effects but - more commonly - by both.