Core jaime is a much better card, totally honest here but this is season 8 Jaime, terrible card, would be much better if this could keep cards discarded and/or have the stand as an option instead of relying him to discard a card to stand him.
Players choose the cards in player order. The first player chooses all of their cards first, followed by the next player, and so on until all the players have made their choice. Then, all the cards not chosen are simultaneously placed on the bottom of their owners' decks, in whatever order their owner likes.
When choosing cards in play, you are allowed to choose opponents' cards if you like. You cannot choose cards in an opponent's hand or shadows area though.
Plot cards, duplicates, or any other cards that are not mentioned in the text of The Mad King's Command remain unaffected.
If a character or location not chosen has an attachment attached to it, that attachment will also be placed on the bottom of its owner's deck if no player has chosen it. It makes no difference whether the attachment is terminal or not. If a player does choose such an attachment and it is not terminal, it will return to its owner's hand. This may cause a player to end up with more than 3 cards in hand after the entire effect resolves.
When cards are placed on the bottom of the deck from the two hidden areas (hand and shadows), no hidden information is revealed. Do not show those cards to your opponents. Same if a card was in play facedown before being placed on the bottom of the deck.
You can choose a character with "no attachments" for this event. That character will still gain renown, but the second part will not resolve, so the event will be placed in the discard pile.
If you are playing A Mummer's Farce, the Forced Reaction on the agenda will trigger for any character that has "Florian and Jonquil" attached, and you will be able to marshal or play those cards. Note that "Florian and Jonquil" does not become a facedown attachment itself though, so you cannot play it again in that scenario.
If the character already had renown, the pre-then part of the effect is still considered to have resolved successfully, so the event will still enter play as an attachment. Same if the character fails to gain a functional instance of renown (due to having a "negative value" of renown beforehand).