Yes to all your questions!

I am a break-taker. I love to stop to walk around and eat about once an hour. If I ride a scenic route, it may be more often. If I am riding with others, it may (or may not) be more often, and if it's cold and/or wet, it's definitely less, because every time I stop I get cold and it takes me a while to re-warm up again.

I ride metric centuries by myself or friends or my club once in a while. I don't do anything special for these rides (except have more food, two bottles of water/energy drink, etc.) except if I'm going to be riding in deserted areas for a while (in which case I will take an extra tube and even more food). If riding by myself, I will make sure someone knows where I am going and when I'm going to be back.

I very rarely ride 150 km by myself, but the same as above (deserted areas) applies when I do.

welcome to TE! Enjoy the sport!