Regarding their canonicity, I don't think trying to determine different grades of fanon/unofficial is something that will work well.
I was going by the Sarna BTW approach, which has 3 possible attributes:
- Canonical (as per Herb's definition);
- Apocryphal (produced by an official source but not canonical)
- Non-canon (fanon, fan-fiction)
Seems to work fairly well.
Apocrypha technically fall under Non-canon, but as a matter of fact there
are different grades of apocrypha.
Some apocrypha used to be proper canon (BattleTechnology, StarDate, Update flyers), some are treated as near-canon even by TPTB (Crescent Hawks, MechWarrior and MechCommander computer games).
Some fall in the middle ground - original German products that were never translated/published in English (a batch of novels and some original FanPro products), BattleDroids 'Mechs like the Ostroc mk2 that weren't carried over to BattleTech 2nd Edition.
And some fall towards the low end of the ladder - like MechForce UK and Germany publicatons that didn't go through any checking or approval process on FASA's/FanPro's side.