Stupid Questions - New Mini R New User

I have a new Mini R that just came yesterday and I’m working on it this weekend. I have a couple of stupid questions that I’m hoping someone can help me with. Thank you for helping out a new user.

  1. The Quick Start guide does not mention powering down before adding drives. Since the Mini-R has hotswap bays, can I just add them with it on? Or is it best practice to power down before adding drives?

  2. I’m planning on making two pools. Each with different sized drives. Should I add all drives of one size and intilialize them and then add all the other drives and do the same? Or can I just install them all at the same time and sort it out afterwards? (Pool 1: 3x3TB, Pool 2: 5x14TB)

  3. I can’t seem to find a spot on the TrueNAS website to purchase the 2.5" adapters. I’m sure I’m missing something. Will any 2.5" adapter work? Or should I find the same brand units? Is there any problem with running m2->2.5" adapters? (trying to use what I have on hand)

  4. I think I want to try SCALE (Mini-R came with CORE). Can I “reverse” back to CORE if I don’t care for SCALE? (SCALE seems to be more active right now - and I’m curious about this with the particular hardware of the Mini-R in mind).

  5. There should not be - but is there any problem with running a Mini-R behind a hardware Firewall (OPNSense or Firewalla)?

Thank you for helping out a new user.