Recipe simply calls for caramalt

All the "Cara" malts are malted for proteins and unfermentable sugars, to add head retention and body. (Dextrin malts)

Usually Cara malts will be matched with the base malt.

In your case carapils, carafoam would interchange with little flavor difference, since "caramalt" is basically crystal-20 with protein malting. Using carapils or other light cara malt will be a slight drop in final SRM color is all.

The recipe uses c-150 for the color which is a strong color addition. Using a simular Cara malt won't effect color too much, and could be made up with slightly more c-150 in the grist. Litterally only about 1/2 oz more as an estimate.

A lot of souces will say Cara malts are the same as Crystal or Caramel malts. They are not the same. http://blog.brewingwithbriess.com/understanding-carapils/

Update: Seems I'm catching a little neg vibe on this post. Let me clairify. All "Cara*" malts are brand names. There's a reason they are protected. The malting and kilning process is different than caramel, crystal, and roasted malts. In short Cara malts have sacharification terminated earlier before kilning than the other mentioned malts. So that some of the endosperm is left unconverted. This is why they add more body and foam than other kilned malts. As a side point. Many don't realize that all the benifiets of Cara malts can be nulified in a mash and they are best to be steeped, also if you mash properly you don't even need Cara malts as you can get the same results from base malts.

No Caramalt is its own thing:

https://bsgcraftbrewing.com/simpsons-caramalt

https://bsgcraftbrewing.com/crisp-cara-malt-15-25-kg

It typically comes in around 15°L, so any crystal/caramel malt in that range should make a fine substitute.