@sylumer you are right. implementing the full specification is hard.
But the front matters typically are very simple I first would stick to the example from @technodad which are only simple key, values except the tag section.
Am I wrong?
My idea is to do the more complex stuff from python3 and use the pyyaml module. That should implement the full speficiation. A draft java script could add a front matter or back matter from the drafts meta data and a json config file in the iCloud directory of drafts.
I started to modify the bulk import markdown script from @gcaprio here https://github.com/42sol-eu/drafts_pro/tree/setup/_scripts