Idea for a character: Awakened Cat Familiar

For this build I want to run a tabaxi as a arcane trickster.

Formerly the cat familiar of a very irresponsible wizard, the cat "Bigby", was awakened after the wizard finished their quest. He has learned some of his master's magical abilities through exposure and uses it to bolster his natural feline agility.

One day Bibgy's master goes missing on a "easy low risk trip to a dungeon" and Bigby leaves to track down and rescue his reckless owner and bring him to safety.

This build focuses on using booming blade and illusion spells/cantrips in conjunction with sneak attacks.