Yeah, this makes sense in conversation. I'm assuming by "out", you just mean "in public". Informally this makes sense.

You can say 'I wouldn't recognise you if I saw you outside' , which is about what might happen in the future, or you can say 'I wouldn't have recognised you if I had seen you outside', which is about what could have happened (but didn't) in the past. Both sentences are ok, but it's not ok to mix them up.

no, there are small mistakes. "I wouldn't have recognized you if I saw you."