Maz would be the easiest character to incorporate into the final season of the Clone Wars. She’s over 1,000 years old so she’d definitely be alive during this time period. Her role in being kind of a sanctuary of the underworld would easily fit into many of The Clone Wars’ storylines and with many of its characters.
There have been plenty of characters in the Clone Wars with ties to the seedy underbelly of the galaxy. From space pirates like Hondo Onahka to bounty hunters like Cade Bane, any of these shady fellows could find refuge in Maz Kanata’s neutral, no-questions-asked castle.
Ahsoka herself has had dealings with the underworld of Coruscant and if she finds herself on the run could definitely find some relief and safety in the neutral confides of Maz’s castle. She could even see Maz as a type of confidant that she could air some of her grievances to about the Jedi Order since Maz is also a Force-sensitive being who has not chosen the path of the Jedi.
Seeing Maz Kanata in the final season of The Clone Wars would be a great tie-in to the Sequel Trilogy and help strengthen the bridge between all eras of the Skywalker saga.