I've been playing around with false colour renditions for composites using both Visible and Infrared. This is to simulate the Kodak Aero Ektachrome IR film of the post WWII era. But I've not tried it successfully accompanied with focus stacking until now.
In brief, a set of focus stacked images was made for each subject in Visible light, and then through an IR filter. The resultant stacks were then combined in PhotoShop to show the IR as red; the red as green; the green as blue. Healthy plant tissue shows as magenta.