I'm answering your second question, which is:
Also, I've noticed there's a lot of similarity between making pulled beef and beef broth. Can it be done in one go?
Yes, you're making beef broth in the process, but I wouldn't add more liquid than the recipe calls for. You want the beef to braise in the pressure cooker as the pressure speeds up the process; you don't want to just boil the beef to flavor more liquid. You're braising because you want that flavor to stay in the beef as much as possible.
With pulled beef, you will invariably have some liquid left over that you can use for dipping sandwiches, or to help flavor your next batch of pulled beef or as a base to make more beef broth, where the goal is to flavor the liquid as much as possible.
Add some of the leftover liquid to a pot that has some roasted beef bones, vegetables to your liking, scraps, etc and some water, and you will be on your way to a great beef broth. Your leftover braising liquid will have given it a head start.
But remember, when making broth, it's all about pulling flavor out of what you put into the pot and putting it into the liquid. When you braise, the point is to minimize loss of flavor to the liquid, and re-introduce whatever flavor you lost to the liquid back into the meal.
So while it's great to use home made beef broth as your braising liquid, or to start a beef broth with some leftover braising liquid, the two tasks are rather exclusive of each other.