I’m not sure where you got your first choice ideas from, but it seems like in every example, your second choice (when you ask “Why not _____”) was actually the correct one.
The exercise is rather absurd, because it’s so unusual to talk about football playing in the passive voice.
It’s an especially weird idea to discuss oneself playing football in the passive voice. It would sound like someone is ashamed that he has played football and is trying to hide the fact.
Making those sentences passive will result in sentences that no one would ever really use.