The first is fine, the second is not proper English. "Will be" is in the future. You can say that "the dishes will be washed at 8 tonight" or "John will be washing the dishes at 8 tonight", not a mix of both. "Ed" at the end of a verb generally makes it past tense. "He washed the dishes (in the past)". "He will be washing the dishes (in the future)".