Question about brackets

So I have 2 questions about brackets I was hoping people could help clarify. I know live by the bracket die by the bracket is not the way and it's meant to be a way to gauge power levels easily.

But I bought the family matters precon which has a helm of the host and a combat celebrant which goes infinite and just wins (unless they have a fog or indestructible creature) or other interaction. I'm aware the precon on its own is not b4 or even b3 probably so where does that combo lie

The other question I have is my friend has a glarb deck with a 2 card zaxara freed from the reel combo. Would you say that is bracket 3 or bracket 4 because with being able to play off the top you generate infinite of any color mana and can just churn through your deck until you hit more lands than you can play.

Any thoughts would be appreciated