Well, Orthodox Ethiopia is a little under threat. Although, the real reason why a lot of the people who signed are muslims is because who actually joined?
1. Afar National Democratic Party (ANDP)
2. Benishangul-Gumuz Democratic Party (BDP)
3. Oromo Democratic Party (ODP)
4. Amhara Democratic Party (ADP)
5.Southern Ethiopian Peoples’ Democratic Movement (SEPDM)
6.Somali Democratic Party
7. Gambela Peoples Democratic Movement (GPDM)
8. Harari National League (HNL)
A lot of these regions have muslim leaders or have large muslim populations. Somali, Harari, Oromo, and Afar have a substantial muslim population. Although Amhara region is around 85% Christian and makes up a large amount of the Ethiopian population. Same with Debub and Gambella. Further more, States that didn't join such as Tigray are 97% Orthodox. The Ethiopian Prosperity party is just Abiy sucking everything in together so he can get a better grip to continue this mess. The Orthodox church needs to implement better techniques, muslims and protestants are rapidly growing because of their offensive techniques to gain followers.