Odia / Oriya questions around ligatures and conjuncts

[n8willis]

I was trying to refamiliarize myself with ory2 this weekend, and ended up a bit more confused than when I started. This may not be shaping-engine–related subject matter, but...

Wikipedia makes a distinction between ligation and cluster-forming behavior that (as far as I can tell) the Microsoft script-shaping-docs do not. Seemingly, it classifies shape-altered-subjoining and mark-form substitutions as "ligatures" (or "northern" style) and reduced-size-subjoining substitutions as "conjuncts" (or "southern" style). Whether it's called ligature or conjunct in English is probably not important, but the table suggests there are some per-consonant rules and I'm not able to match them easily to the other docs....

Unicode calls special attention to "nasal and stop clusters". The now-deleted page I first consulted on Oriya back when drafting the initial doc (Wayback link) similarly made sharp distinctions: specific nasal forms, specific half-forms, specific conjunct & diminutive-form rules.

It seems to be noticeably more difficult to find Odia/Oriya resources written in English, so I would like to put the call out for anyone who has experience to please weigh in, both on whether the current doc here (and on the Microsoft site) is complete and on whether or not some of the distinctions alluded to in the links above are relevant for a shaping engine (or are more of interest to type designers, for example).