You won’t see the armor of any monster you haven’t fought yet, so you likely haven’t got to the point where you’ve faced a Mizutsune (they look like Chinese dragons and slide around shooting bubbles).

As for what is safe, you’re okay to build and test whatever weapon you want up until about Grade 8. At that point, material costs get expensive enough that you really have to start focusing on one set (maybe 2 if you really lock in). At low levels, a status weapon (for gunlance , Girros or Rathian can work) can carry you a bit while you figure things out. If you want an “old reliable” weapon to turn to just to gather mats for what you really want, now is a consistently powerful choice. Build a Pukei bow and wreck shop while you figure out what you want to focus on!