Sounds delicious! I'm always looking for more uses for Falernum. Also, a good excuse to get a new Amaro, so it's perfect! I also kinda wonder how it would work with a Charanda instead of Mezcal... Could be interesting.
The original recipe called for Aperol, so you don't have to go exotic with it if you don't want to. I just like Bruto Americano instead of the sweeter orange amari.