I'm not sure if this is the right place to post this.

For regional events, is there a restriction on what sets are legal? Meaning will the Lunar cycle be legal for regional events when they are released, or is it just up through Honor and Profit that are legal?

The Tournament Rules cover this, but in general whatever is generally available at retail is legal for tournaments. So, for example, last year Opening Moves was a special pre-release at Gen Con, but was not legal for the tournaments there, since it wouldn't be in stores for another month.

If a card has hit general release via datapack or deluxe, it's legal. If a card is available in draft but NOT yet available in a datapack, it's not legal.