It's sketchy, but could Mopper have it at the Speed Bump?
They definitely get it eventually:
Looking at the sand(which is same as beach sand) and the raised highway tells me that they are close to a major Bridge and still in the coastal area. Also, with respect to the relative location of other teams Art&JJ at Mattanchery and Ralph&Vanessa south of that doing the coir work , i think this speed Bump is somewhere south of Mattanchery near one of the Aroor Bridges(there are several of them and it's not easy to pinpoint which one due to lack of clues).
There are shadows when Mark and Bopper do the Speedbump. Perhaps Chateau can work the magic to predict the time of day this was taken. It would also help determine if it was an extended RB of 24 hours, instead of 12 or 18.
Order of finish last leg was:
Dave/Rachel
Benchel
art/JJ
minute behind them Vanessa/Ralph - on mat together.
Bopper/Mark, approximately 3 hours behind Dave/Rachel.
It's daylight (overcast) when Dave/Rachel receive a greeting and get a clue/dots from high priest which would indicate a 24 hour pit stop unless Hoh. I feel extended pit stop.
Vanessa falling/Ralph could be them racing to go after FF since they aren't to far behind Brenchel at Pitstart.
We know Brenchel arrive at FF, but since it required shaved heads after stacking 150 bales of hay, they opt out of FF before doing anything. That's why they catch up with Vanessa/Ralph, Art/JJ at RB. This would lead me to believe RB was before Detour, but I have no proof of that.
We know Mark/Bopper are doing speed bump and the skies are blue with clouds. It would indicate some time later than the overcast skies when Dave/Rachel started the race leading again to an extended 24 hour pit start time.
Now the big question comes up even though I've been watching faithfully since Season 1, when teams receive the clue that a FF is available, do they know if it is used yet, or do they have to go to FF location to find that out. I think the later.
Would Mark/Bopper feel that Brenchel or Vanessa/Ralph went for it so would not even try, or would they take a chance?
I guess you refer with "dots" to the bindi in team members foreheads. If it's right, you're wrong. The High Priest is giving a clue to teams after they completed Detour "B", and there's a cap of Art performig this Detour with the bindi, and from Rachel & Bendon on the other Detour when you can also see the bindi in her forehead. So the bindi is previous to their meeting.
The hay stacking was the FF that Dave & Rachel won in Azerbaiijan (leg 6), this FF requires only that members of the teams shave their heads (as in TAR2, TAR5 and TAR7).
I also think - as you do - that RB is probably the first task of the leg, the same way it happened in the two previous FF of the season (Italy and Azerbaijan), and Rachel facial gesture at the RB could be because she had an argument with Brendon about the reasons of not doing the FF (remember all the drama in Italy's leg), or for being catched up by all the other teams behind them at the RB.
According to this, you're wrong with the spec that Vanessa's fall was in route to the FF: you can see her in the clips walking without problems at the RB.
About Mark & Bopper, if the SB is before the first task, they could take a shot on the FF when they return with the pack, if they saw all the others teams still doing the RB.
And the only way to know if a FF is taken, is to going to the location of it. Remember Nick and Vicki in Season 17, and their confusion with the "Fast Forward taken" post in the door of the FF's place, after Nat & Kat won it.