A:AnswerThe right can be used independently with the left bud still in the case. The reverse wouldn't work. These earbuds are not great though, I'd keep looking.
A:AnswerCAN you, yes. Should you probably not. Like with most electronics, the steam and water could/will damage it and may give you a tingling sensation for a bit.
A:AnswerYes exactly the same way. I own both because the AirPods don’t stay in my ears on a hard run. These fit amazing and have never fell out. Sorry Apple.....