D&D 5E Questions!!!

[Jester David]

Pretty clearly Ready is the general, as it's presented in the general rules section, while Moonbeam is the specific, as it's text only applies to Moonbeam.

Kinda.
It's not "on your turn" though. It's "on each of your turns", which is the statement they use to emphasize you can do something on each new turn you take rather than just once or on every turn.
It's an action you can take on your turn, so Readying it seems reasonable.

Both readings of the rules are acceptable. It's going to require a DM ruling. Table variation ensues...

Personally, as Readying spells requires you to concentrate, and moving a moonbeam when Readying is advantageous, I'd rule at my table that the spell ceases to have an effect when you Ready, still being present but shifting and not dealing damage until you take your Reaction. That way you can't delay moving to hit two different groups.