Aircraft Maintenance Tech here, this is not a Boeing QA problem, nor did it cause an unsafe scenario, but did prompt a return to gate. On these aircraft the windows are a laminated tempered glass/polycarbonate sandwich almost 3/4in thick and are designed to survive impacts at high speed with large birds, ice and hail. I have personally shattered one once and the window was still perfectly structurally sound. The most common fault with the windows is either a delamination of the layers that causes a warped area of vision or the electrical heating elements go bad/start arcing inside the pane. Both scenarios happen say once every 6-8 months in a 15 plane fleet, so not very often but it does happen. The maintenance limits are surprising too,only need to be replaced if it limits the pilots vision(their call) or if the heater doesn’t work or is arcing. I’ve also seen pilots call small things “cracks” or other imaginative language and it was a small thing, still needs to be fixed but not worth the drama. Long story long, things wear out, things fail but don’t worry about the windows, they are gonna hold.

Those don’t seal well, so probably not

Aircraft maintenance has been doing the negative pressure unlock tests on cockpit doors for decades, its honestly surprising what isn’t common knowledge. Like others have said, rapid decompression of only a portion of the aircraft is very bad, and will result in massive structural failure as individual compartments aren’t pressure rated and will blow apart. The doors I’ve had experience with had large panels that would pop out when in a negative pressure event.