Well its only just to arrest someone who violates the law, this as far as I know is attempted murder. Apparently she is using bitcoin to pay is just not making it bad for the reputation. It would have been good if coindesk also get the whole story as to why she wanted the guy dead.
Yes. Hiring a killer should be done in a chain and with familiarity.
Not directly
Unfortunately, people think that everything is like a movie

I'd say it shouldn't be done at all
There was a case years ago in the US where a woman tried this "chain" youre talking about. She contacted her friend and asked if he could help her find a killer because she wants to get rid of her husband. The guy went straight to the police and they sent an undercover officer to record her describing all the details.
Don't do it people!
I've seen this on TV. She still deny even after arrested. Seen lots of crime documentary, reasons are mostly about money, new love and kid's custody.
I would also add violence to your list as a reason to take revenge on the offender in the same way, but only more "effectively".
Perhaps her husband beat her, perhaps also threatened her with violence.
And in general, apparently, this woman did everything quickly, was emotionally unstable and didn't know much about cryptocurrency transactions, so she made so many mistakes.