Q: Can a third party (non-author) submit a manuscript to a journal?
Whether a third party can submit a manuscript to a journal depends on the publication policies of the country where the author is based. For instance, it cannot be done in China, irrespective of whether you are submitting to a regional or an international journal. Each country has its own publication policies and you will need to check these before submission. Your librarian should be able to help you in this matter.