Hogs are evolving and it is likely different sounders have different habits. Hybrid Hogs have some different habits from true Boar.
True Boar, the sows only breed once a year (usually around the first hard frost here). The grown Boars (18 months or older) may trail the sounder in the early fall, but are usually off by themselves or sometimes in young brother pairs. The Sows usually won't tolerate a full grown Boar in the sounder as long as there are squeakers around. The old timers say it is because sometimes the grown Boar will eat the squeakers. I've seen some really noisy fights when the lead sow drives off a grown Boar. Likely different with Hybrid Hogs, they come in season any old time and the social dynamic changes some.
*Most* times when I saw a single or a pair of Hogs come in early to feed they were around 18 months old and sows. I always figured they were know it all teenagers and weren't real big on following orders. They broke off from the sounder and cut corners or ran ahead to be the first on food.
The idea of them sending out scouts is new to me, but I don't doubt it. Pigs are way smarter than most Dogs. I've seen them weave a route through the countryside trying to avoid shooting towers, stands and choke points. The only reason I can think of for them to take the long way around consistently, is to avoid danger.
I've also seen them travel in formations, very much like a infantry platoon in enemy territory. Too precise to be an accident, topping a hill in a line abreast formation (shoulder to shoulder) then switching to a rough V formation with the squeakers near the middle.
Most times they travel in a gaggle, with the lead Sow near the front and two or three Sergeants (grown Sows) kind of surrounding her. Sometimes the teenagers (18 months or so) try to break ranks and race ahead. I've watched the lead Sow beat the heck out of teenagers and bully them back into the pack, to keep them from breaking cover and heading into a clearing.
Usually when I am hunting a grown Boar, I watch a sounder come in to eat and then wait for up to half an hour (or more) for a Boar to show up. They often trail the sounder. And often don't mix in well, the lead Sow positions herself between the Boar and the rest of the sounder, it appears adversarial most times (10-11 months a year).