As it stands, there no Foam optimized templates for those helmets. But what you need to understand is that:
1. All of our free files in the Armory are those files that have been generously donated by Members of this Community for the better of all other members and potential members. The files in the Armory are the fruits of the labor of many dedicated Volunteers who just want to help other people who want to make Halo costumes. As such, since these are the works of those Volunteers who are willing to freely give away their files and unfolds, Yes there might be some holes in our collections, some missing pieces or unfolds because the small community of those members willing to put in the time and effort to do these free unfolds is only human and the amount of possible Halo armor costume pieces and props to unfold, both in Pep and Foam is a staggering task. An enormous amount of files coupled to a small community of free unfolders means that some times it can take awhile to get around to things or some things won’t get donated in the format you would prefer.
2.Foam is not the most desired medium for Helmets. Due to the intricate details present in most Helmets, even our most dedicated Foam builders will often use another method, pepakura, resin casts, or 3D printing in order to capture the best result possible, as the helmet is often the focal piece of the costume and can make or break the whole thing. It takes a very dedicated or talented Foam builder to craft a Helmet and as such the Helmet is most often left out of many of the Foam Unfolds.
3. Our Foam Templates in the Armory are all based in Pepakura anyway, so, it is entirely possible to take those existing templates and use them with Foam. There are many guides out there on YouTube and even on the Forum here that will show you how to take a normal pepakura file and optimize it for foam.
4. If you do not want to try and do your own Foam unfold, there is a member that takes requests for Foam Unfolds, but again they are a volunteer doing this in their Free Time for the good of the community, so there is no guarantee or when or if they could get around to accepting your request:
ODCA's foam unfolds (and unfold requests)