The issue is that her being updated or not shouldn't allow her to count Nim as a friend as they never once really interacted. This doesn't change regardless if she went to go help save Nim or not either as I'm not taking issue with her dialogue pertaining to going to help save Nim with Melia and the player character, but her trying to appeal to being her friend when they had never interacted. She should realize that Nim wouldn't recognize her back anyways (she shouldn't be aware that Nim was watching her gym battles, nor was she ever hinted at being aware of this.) Venam's, "We're friends right?" and her questioning, "Why the hell not? when Nim said no in this case comes off jarring due to this. That doesn't organically flow with your explanation as Venam comes off as believing that Nim would recognize her back as a friend. Crescent messing with her memories also doesn't explain Venam's side, nor does it really fix things as it forces the players to assume that Crescent had added memories of Venam with the group earlier than she had come in. The only alterations we are shown are that she believed that she was forsaken by everyone else and that only the player character had come to save her.
I could see Venam recognizing her from having seen her stone state, but I feel like she'd not have had long enough time to see her given how quick the whole series of scenes took place. Remember that Zetta and Geara caught onto Melia's deception quickly and Giratina had intercepted the player and Venam's attention not too long after. Venam in particular is the first one to see Giratina and is watching it for the whole time it appears. After Jenner tries his rescue on Nim, Venam then ends up battling a grunt in battle. So while I could see this being least jarring, it still requires me to apply suspension of belief to fully believe it. Venam has been shown to be perceptive when she needs to be so it's not entirely out of the ordinary, just hard to believe given what I said.
Braixen had not come along with Saki, Valerie, and Adam. Adam states, "Braixen is lucky she didn't have to ride on this thing...I think I'm going to be sick..." This destroys any chance for Venam and Braixen to have logically interacted with each other. As Venam is with us from receiving her help with getting Amber to move to the events of Valor Mountain. In this time she only interacts with the player character, Melia, Valerie, and Saki and only sees Adam at Valor Mountain.