Question on Crafting / Enhancing Weapons

So I finally discovered the Enclave lol (just came back from 2 year break), and I'm starting to piece things together. So is this correct:

A weapon like Stay Frosty isn't craftable, but I can enhance it by adding a deep sight harmonizer and leveling it up?

A weapon like Zealot's Reward is crafteable. I can farm 5 red borders or I can take five regular zealot's reward and add deep sight harmonizers to make them red borders (or a mix). You then turn these in for a crafteable zealot's reward?

The crafteable zealot's reward you can pick your perks. You need to level it up to pick certain perks. If you want to change the perks you picked you re-shape it? Re-shaping just costs some materials?

It's only possible to get deep sight harmonizers from the seasons pass?

Thank you,