Zwift has a nice variety of “focus” celebrations and months. Wouldn’t it be nice to add one for Veterans? There are lots of us out here who would appreciate it even if it were as small as an event focused around Veteran’s Day or Memorial Day. If that isn’t possible I sure would enjoy riding in a well designed USMC jersey.
The holidays you mention are based in the US. This is an international product, so something based on the calendar probably would not work (ie, PLA Day in China is not at the same time as Veterans Day in the US). Probably better to have a community organizer like USMES put on those events if you want to keep the focus on US vets.