Can epigenetic structures cause a trait to manifest in a person if the trait is not already in the DNA? In all my readings I have yet to find a definitive statement that it is impossible.
Yes, epigenetic changes does affect the phenotype. This is here the whole interest behind epigenetic. Environmental variation (incl. parental care) affect epigenetics which in turn affect the phenotype (incl. behaviour) of an individual. It is pretty much clear from the wikipedia definition of epigenetics
Epigenetics studies stably heritable traits (or "phenotypes") that cannot be explained by changes in DNA sequence.
The term "phenotype" (or "phenotypic") is actually present 3 times is the first small paragraph of the wikipedia article.