Bro

and get executed? because emperor still thinks she's a madwoman brah

I'd risk it, just let him see me turn into a swan.

so he would think she's using her own witch powers to trick him

Don't think he would go that far, she just needs to tell him and all the other brothers. There's already suspicious reports of things going on in her block of the castle; she just needs to pull off that plot armor stuff and I have them promise not to kill her then she'll show them.