I have a few answers:
2) Season 4, Leg 11- Jon and Al tried to get on the same flight as the other teams, but their Race-provided credit card was not accepted by the airline due to computer problems, and they were unable to make that flight. As this was an airline issue that production could not control, production held up the other 3 teams when they arrived in Australia to make up for the time lost in resolving the card issue, and thus appearing to have all teams equally bunched out of the airport. (They got elim'd anyway that leg, so oh well)
I'd also argue that production unofficially steps in to stop teams getting ahead every time there's an hours of operation bunching point midway through a leg, but that's more of an opinion than a fact.
5) While it may not officially be the longest leg on record, as far as the longest task to complete, that would probably be Season 6, Leg 3, by Lena & Kristy, who spent between 8-10 hours trying to finish the hayroll RB and probably would have gone on longer had Phil not shown up to eliminate them before they could finish.
7) I don't know the history of RFF's spoilage, but one could argue the first time RFF's spoilers became infamous was when it leaked the complete boot list for TAR: All-Stars (Season 11), which was 100% accurate.