Another thought related to the idea that the Mon Cal cruiser and bombing fleet is the final form of support from the Republic:
Vice Admiral Holdo could be explicitly identified as part of the Republic military.
For backstory purposes, she was only to be the one in charge of delivering the ships to the Resistance, except that when the Hosnian System was destroyed she became a member of the Resistance by default.
This would make Poe’s suspicion of her more believable, and make her role in the story more meaningful - she’s the last of the New Republic (as opposed to the Resistance) military leadership. Even her sacrifice is more poetic, since she’s more explicitly avenging the destruction of the New Republic.
How are you going to pull that one off?
The same way I pull everything off, Pinky!
By including it in the crawl?
Thinking cap on!
Maybe instead of having some random official tell Leia that a ship is on its way in TFA, there could be an image of Holdo on the screen and there could be dialogue from offscreen:
"General, the Vice Admiral of the Republic has pledged her support!"
Or maybe see if there’s any of Laura Dern’s dialogue from another movie that could be used for this purpose.