Plot hole: It shouldn't matter if the neighborhood's got a petition. If the tree in question is on Mrs. Claxton's property then they wouldn't have a say in the city removing it.
Plot hole: In the flashback, neither Dorothy and Stan nor Sophia and Salvatore own a TV yet. Still, Sophia knows exactly what shows each of the four like. It's unlikely Sophia regularly watched TV before as Dorothy believed her when she lied about thinking a TV is a waste of money.
Plot hole: Dorothy's son Michael is twenty-two years old in season three. When Sophia and Dorothy reminisce Brooklyn, NY, 1954, Dorothy asks Sophia to babysit her children, one of whom is Michael. Sophia refuses, so Dorothy says "I'll just leave them with Stan's mother." They talk about Michael screaming when Stan's mother was watching over them. If Michael was a baby in the fifties, he should be in his thirties in season three.
Plot hole: At the end of this episode, the lady who was on the TV show with Blanche and Dorothy as "partners", shows up to ask Dorothy out because her and Blanche broke up. She says "I heard about you and Blanche". How could she have heard it? They just did it at the house.
Suggested correction: We have no idea how long it was between their 'break up' and this scene. In fact, the scene where the woman asks Dorothy out occurs during the final credits. Dorothy is wearing the same clothes she had on during the 'split', so yes, it wasn't long after. Maybe she saw Blanche out on her date with the guy that broke them up and asked her about it.