I respect Merida several so if choosing the pets for Merida I'd choose pet who'd stand out easily I'd choose a kite who enjoys flying close to Merida and likes to help her navigate but alerts her if it thinks they're not far from danger. I'd pick a badger because of the symbolism it has in Celtic culture and with its symbolism I visualize it showing the whole palace loyalty, for a dog to really stand out in the Palace Pets show I'd give Merida the Shetland Sheepdog, and if also choosing another cat but letting it stand out too it's the Scottish Wildcat I'd choose.
A small group of palace pets for Merida this type of group from Scotland could be quite playful whether showing natural reaction or borrowing the zodiac and symbolism of Merida's culture. These four would even be gentle enough to play privately. Kite, Badger, Shetland Sheepdog, and Scottish Wildcat, a team like this wouldn't mind if they were outside in the open or inside exercising in a social way with toys.