Hi Chipp - The only way that I know to get from MoI to Alembic via OS X is to export OBJ or FBX from MoI, then into Maya or C4D to then export to Alembic Cache (*.abc), not perfect i know since again you will loose those lovely smooth curves from MoI.

Martin
(TpwUK)

** Edit **

Oops forgot to mention that you will need to create a planar surface before you can export FBX or OBJ - My apologies Chipp