The creation of missions for this Reforger is still in its early stages. I think, there are no an attribute array yet that we can use for every xxx.json files.
Only the creator of mission can provide attributes or information that are appropriate for the mission's menu items. Request the information.
When you have the necessary information, you can attach it to the xxx.json file. Add the information/attributes you want to this missionHeader. For example
"missionHeader": {
"m_eAiSkill": "Regular",
"m_iStartHours": 10,
"m_xxx": xxx,
"m_xxx": "xxx"
}
and so on.
To avoid server errors or crashes, it is a good idea to find out the min and max values of all parameters that can be used in the attributes. It is also important to note that the parameters also have text fields in addition to just numeric values. The creator knows this information too.
If I'm wrong, someone can correct me on that information.