No, because there’s a good argument to be made many 18 year olds are not mature enough yet to consent to life decisions, let alone 8. We just have to draw the line somewhere.
If they have consent from everybody in that place, sure.
See #2
See #2. Though that might bring up other issues like encouraging violence, etc.
For #2, if you aren’t involved in the act, but don’t consent to witnessing it, then aren’t you just being intolerant?