[Solved]: Are all DFAs also NFAs?

That depends on how pedantic you are. Morally and semantically speaking, every DFA is an NFA in which there is a unique arrow exiting every state for every character in the alphabet, and there are no $epsilon$ transitions. Syntactically speaking, it depends on your definition: the transition function could be encoded differently, so that the transition function of a DFA might not be “legible” for an NFA simulator. I would not worry too much about the syntactic viewpoint.