0:41 - Zeb (to Rex, after Ezra asks if he's sure he won't go with them): "Yeah, you're not bad in a fight." Han similarly describes Luke in A New Hope: "Pretty good in a fight" [1:41:43].
1:36 - Hera (to the rebels): "Good luck down there." In The Empire Strikes Back, an unidentified Rebel pilot wishes Luke good luck [36:02] and Luke wishes Lando good luck [2:00:09], and in Return of the Jedi, Han and Lando wish each other good luck [Han to Lando at 50:33 and Lando to Han at 52:21].
4:19 - Sabine (after Gregor says the clones haven't been shot at in years): "Yeah? Well, it happens to us every day." There's some similarity here to what Indiana Jones says in The Last Crusade after his father tells him that someone trying to kill him is a new experience for him: "Happens to me all the time" [1:18:43].
5:18 - Agent Kallus (to Admiral Konstatine): "Prepare for ground assault." General Rieekan also says this in The Empire Strikes Back [22:42].
6:48 - Gregor (about the AT-ATs): "Would you look at the size of those things!" Wedge makes almost the same comment about the Death Star in A New Hope: "Look at the size of that thing!" [1:45:53]
7:10 - Rex (after Kanan criticizes him for running from the AT-ATs): "Well, if you've got a better idea, sir, now's the time." Obi-Wan says something similar while speaking to Tion Medon in Revenge of the Sith: "If you have warriors, now is the time" [55:19].
7:41 - Kallus (to the AT-AT pilot): "Fire at will." Palpatine gives the same command in Return of the Jedi: "Fire at will, commander" [1:14:37].
9:12 - Sabine (referring to the AT-ATs): "Those things are practically impervious to blasters, but they have one weak point in their armor: the neck."
Gregor: "One well-placed shot from the main gun should destroy it."
There are two similarities here. In The Empire Strikes Back, Luke says of the AT-ATs, "That armor's too strong for blasters" [27:20].
In A New Hope, General Dodonna says of the Death Star, "A small, one-man fighter should be able to penetrate the outer defense" [1:39:43].
9:50 - Zeb: "I don't know how we're supposed to shoot something we can't see." There's some connection here to Luke's comment in A New Hope: "With the blast shield down, I can't even see; how'm I supposed to fight?" [1:01:41]
14:49 - Rex (to Ezra): "Great shot, kid!" Han says the same thing to Luke at the end of A New Hope: "Great shot, kid! That was one in a million!" [1:57:20].
16:48 - Kallus: "Intensify forward firepower!" Admiral Piett says the same thing in Return of the Jedi [1:59:00].