Some changes I’d suggest:

As everyone else says, make sure it’s obvious Holdo is afraid of traitors
Get rid of the stupid “shuttle parkers” gag. If the audience knows the heroes are dumb for doing that, don’t have the heroes do that. Instead maybe have Rose give a starving child some food, and have the authorities think that’s suspicious and follow her as a person of interest.
Have the Master Codebreaker and DJ be the same character. Maz Kanata ought to warn our heroes at the start that he doesn’t work for cheap, but Poe & Finn & Rose are so eager to save the Resistance they’ll promise him the moon. Later, the Codebreaker shows up to break them out of prison, after seeing them get captured just as they were about to find him and being intrigued. He’s the one who betrays them on the Finalizer, for money, because he doesn’t think the Resistance is profitable and he’s doesn’t care about the morality.
Additionally, I’d imply (but not necessarily state outright) that Snoke is an ancient creature, somebody who was a member of a primeval “First Order” that predates the Jedi and Sith. Perhaps he’s now broken out of some ancient confinement (maybe something on Ahch-To like that giant pit)?