I suspect they'll limit it to reimbursement to one MIGS...

I suspect they'll limit it to reimbursement to one MIGS procedure at a time although they might allow both if there are studies that show they have a synergistic affect.
Both stents and canaloplasty are relatively cheap procedures compared to the major trabeculectomy op. They can do one MIGS op then another down the track but they're often done under GA ( minimum sedation) & always in a theatre so the additional expense involved with multiple surgeries is ridiculous they would be better just allowing both MIGS procedures at the same time.
But you're dealing with pen pushers not clinicians so they often make the wrong decision initially then change their mind once they see what happens in the real world