OK, so what is  "Missionary License"?
At one time a Missionary License was issued to  just about anyone who worked for the denominaiton and was not issued one of the ministerial credentials.  A review of listings in a recent YEARBOOK leads me to believe that this is still somewhat the practice, with some changes.
Present credentials are:  1) Ministerial Credential,  11) Honary/Emeritus Ministerial Credential, 2) Commissioned Minister Credential,  22) Honaryl/Emeritius Commissioned Minister Credentiall, 3) Commissioned Ministry of Teaching Credential,  33) Honary/Emeritus Commissioned Ministry of Teaching Credential,  4) Missionary Credential,  5) Administrative Ministries Credential.
Persons who have Licenses rather than Credentials are not commonly listed in documents such as the YEARBOOK.