I wanted to do what you suggest - have a planted tank with a number of butterflyfish. I tried growing macro algae in my tank (Shaving brush, maiden's hair, halimeda, and a couple of others, but no caulerpa) with no success. I suspect one or more of my butterflyfish had a hand in the demise of the algae, although I can't say I ever caught them picking at the algae a lot. The suspects are a ulitensis, falcula and saddleback. I now have two tangs so macro algae is not going to grow.
You might try getting the algae established and then introducing the butterflyfish.