The whole scene makes very little sense. It would be much more logical for Reva to present herself as a friendly face, and a representative of the Empire put in charge of bringing Leia to the safety of her parents, in hopes of getting at least some information. All Leia knows is, that she was taken by some pirates, and then apparently rescued by a former Jedi, who themselves are wanted criminals. There’s no subtlety in Reva’s character. She’s just a one note villain, who’s inept at interrogating a little kid, fails to recognize her innate Force ability (which is her job), and wants to torture her for information, she likely doesn’t have. Presenting a friendly face would make the Reva character more interesting, and competent, being able to do more than just yell and scowl.
Glad to see this, that moment also stuck out to me as really Disney-fied like they’re playing to the kids out there who see themselves in little Leia. That’s fun in an interactive theme park setting and ultimately Star Wars is for the kids more than the adults, but for a serious scene the more intense the interrogation got the sillier it was. If Reva handled the situation like you suggested (which is how real interrogations typically go) the whole scene would improve, Reva would have more dimension as a calculated villain instead of her usual one note, and Leia by rejecting her manipulation would reinforce her inner wisdom and even call back her skepticism of Kenobi in episode 2. I get it, the inquisitors are ruthless and it’s sort of been established that force mind reading is Reva’s thing, but in the wrong scene with the wrong character it can (and in my opinion did) go over the top and feel even cheesier than all the last minute saves.
Reva better break out that backstory soon and it better be worth it, right now the more she tries to act scary the less intimidating she gets, the character is becoming a cartoon.
For Reva to take a calm approach to interrogation would be against what they have established for her character. She seems stuck in the bad cop mode (not surprising for an angry inquisitor who has already been established as reckless). It might have made the interrogation more useful.
And the symbol she saw and pulled off the wall was a Jedi symbol, not a rebellion symbol. She’s grilling Leia to see if she has anything on this. The chance of Leia having any useful information (if you look at it logically from Reva’s perspective) is very low. I’m certain that with his close association with the Jedi, Bail Organa is being watched closely. But there is a chance. We already know that Leia doesn’t know anything more than what we have seen. Bail is in on the formation of the Rebellion and isn’t involved with getting the Jedi to safety.
Bail doesn’t move into action until the Death Star changes the game. He doesn’t risk Kenobi again. And likely Leia’s message to Kenobi is very coded in case it falls into the wrong hands. If you watch ANH, Leia knows who Ben Kenobi is. She never questions Luke. So she knew that name. And C-3PO makes a number of false statements. He tells Luke he doesn’t know who Leia is even though one of the first things he says in the film is about Leia. So he is protecting their identities constantly until he knows that Luke is truly an ally. He wasn’t privy to Leia’s instructions to R2, and is obviously confused, but doesn’t reveal anything that we know he knows. And with Rebels, Rogue One and the opening of ANH, we know he knows a lot.