I doubt a Mellel plugin is going to happen - it's a good amount of work, Zotero devs have said that they won't do it and I'd guess that Mellel isn't super interested in developing one, either.
One way forward would be to improve the RTF scan feature of Zotero. The other way would be to facilitate getting Zotero items into the Mellel bibliographic database - that would be easier to do via some type of database sync or through the Zotero api.
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One way forward would be to improve the RTF scan feature of Zotero. The other way would be to facilitate getting Zotero items into the Mellel bibliographic database - that would be easier to do via some type of database sync or through the Zotero api.