Lots of topics here, so I'll discuss one by one.
In the video of #7195 driving on the middle lane, I think the narrator is simply annoyed and having a bad day. I don't think the Greyhound driver has done anything wrong in that case, because he is not travelling in a passing lane.
Regarding Seattle, I doubt Greyhound has to store as many as 15 buses in the lot on a regular basis. No, I didn't forget about the Stanfield/Missoula runs, as those are important to me in personal ways, but those two routes only requite 7 buses in total, at least half of which are on the road at any given time. BoltBus doesn't need to store anything as their schedules go to Portland and Vancouver, both of which have plenty of space, and the latter has a fully-equipped Maintenance Center. Same goes for the Greyhound through runs from Los Angeles.
In a pinch, Greyhound could store no more than 5 buses at a time in Seattle. Hopefully KCM has the space. Everything else could be moved to Portland and Vancouver.
I'm not a Greyhound driver, but I understand that new drivers enter the Extra Board, where they drive On Call and get at least 1 day off per week. The other 6 days, they drive 7-10 hours per day, with a minimal of 8 hours rest between each turn of driving. However, the Extra Board means they only drive when they are needed, so a driver could get no work for days, then have to work 6 days in a row before getting a break. Greyhound drivers seem disgruntled and eager to leave the company, so I would not recommend driving for Greyhound.
It is presumably better in loosely-populated areas, where long distances and low frequencies mean even a new driver can have a relatively normal life. I've heard that Salt Lake City can be one of the best bases for drivers, if you don't mind carrying lots of suspicious passengers (due to the large number of homeless in SLC) and driving smelly D4505s.