two simple plumbing questions

Better look into “shark bite”.
My plumber used some when he connected my new shower. They make valves that just slip on. Amazing stuff nowadays
Haha. First time I saw those my plumber buddy was gonna put them in our new house we we're building. I asked what the hell are those things? Don't put them in my house! He slipped one on a piece of pipe said "I'll give you 20 minutes to get it off." I couldn't. Still fine after 10 years.