Spitfire, the clock starts when the BFS document is delivered to Teck. That's all there is to it.
Sedar and the Option Agreement have absolutely nothing to do with each other, nor affect each other in any way.
Sedar is where you officially make something material public for all to see in detail; minority shareholders, public at large, Teck competitors, etc.
For reasons that have been suggested here recently, Copper Fox intends to make the BFS details (400-500 pages?) open for all to see on Sedar BEFORE handing over those details to Teck. Maybe because of Full-disclosure / equal access to new information regulations maybe? We don't know.
Maybe this is just another excuse to grant Teck more time. Or grant another party entirely more time.
The following might offer some clarity on your other question/concern:
* CF is not legally obligated to deliver the BFS to Teck by any specific date, however
* Teck can back-in at any time even before seeing the BFS (Elmer keeps stressing this...), where that would obligate Teck to transfer the Liard shares just as though a Positive BFS was delivered.
* Nothing is stopping Copper Fox from soliciting bids from Teck competitors before approaching Teck to present the full BFS perhaps along with the highest competitor bid.
That gives Teck first right of refusal for CF's interests and would make Teck's buy out decision much easier. Teck would then know what buyout offer they have to beat. If they don't beat it then they let CF's 24% interest go to the highest bidder.
This last scenario is a little tricky. I haven't worked out all the pitfalls of doing that, i.e. possibly pissing off Teck when they find out we have been flaunting the BFS to others first. Some here have said "no way you will get bids when they don't know what Teck will take". I'm not sure I buy that concern. All Copper Fox has to do is tell bidders to bid assuming they are getting the 24% interest since never in a million years would Teck take less than 75%.
Just some thoughts.