Best thing to do is switch it up, that way your body constantly has to adapt.
Always used to think so, but never had any issues not using clips. As long as you keep the bar reasonably horizontal, they aren't gonna come off. Just double check they are fully pushed on before starting a set.
The loss of dignity from getting trapped at the gym with people watching may just be worse than being trapped at home
Yeah, I'm using that sort of dumbbell weight for strength stuff. Never used the kick up technique, I just hold them on my thighs, lean back, and bring them up to my chest (so I start with them low rather than high).