(pax). A bit disconcerted by the talk about using the gear to slow the thing down. Is that really an option in day to day ops and if you do it aren't there subsequent consequences since you shouldn't have been in that state anyway ( well so I assume). Thanks for your patience, I only sit in the back.
Perfectly normal. Gear often dropped early when intercepting the final approach with a tailwind, for example. It's most useful at about 200kts - the gear doors provide significant short term drag and can be what you need to get flap 2 out. I wouldn't consider using it from 10,000 ft because the speed brakes are more effective at higher speeds. The noise in the cabin is astronomical if you drop them anywhere close to the limiting speed.
Neither of the videos shown above seem plausible to me.