Yes

If they have the same hash they're the same event. Interested in why you're asking though

Yeah. The id and sig match on both.

No, the ID and signature are the same but the pubkey it's different so one of those events it's invalid

I would verify the JSON strings before computing the hash/event_id. For example, white spaces or line breaks.

One of those events is invalid. I would tell you which one if I could cut and paste it.