Here is a more constructive comment about the potential Savannah and Charlotte dynamic:
Though Joan already touched on it, the brief history of LBJ is that Gray Wolfe was the first leader. He was a professor at UT Austin and Savannah was a law student when the rising happened. They were already near the library when all that was going down so that's why they ended up there. Gray was the leader from basically the beginning until he got kidnapped in the beginning August by some sadistic people living down in the tunnels. They let a zombie bite him and then threw him out into the street, assuming he would die. The Dog King (Rodeo), aka the Hellhounds' leader (who is currently MIA), came across Gray as well as some Capitol Patrolmen. The Patrolmen saw this as an opportunity to blame Gray's murder on the Hellhounds and get the LBJ to be under the Capitol's control (Gray refused to let the Capitol have patrolmen in the LBJ at the beginning and bc of that LBJ had to trade the Capitol for water rather than it just being given to them, like the UMCB receives). Rodeo didn't want this to happen. He killed the Patrolmen and took Gray back to the Dog Park.
Fast forward to Gray being immune and coming back to LBJ at the end of August... The Hellhounds' rat leaked information to Olinger and the Patrolmen when they were moving Gray so when that happened the Patrolmen met them in Austin and killed Gray. The Capitol reported that the Hellhounds killed Gray. The Hellhounds told Savannah it was Patrolmen. Savannah believed the Hellhounds and they grew into forming an alliance. The Hellhounds provided LBJ with a water source in October, so they haven't had to trade supplies with the Capitol since then, furthering the strained relationship between the two shelters.
Depending on when you were Charlotte come to Austin, she may have experienced that first hand or just learned about it and gone from there. I'm definitely cool with whatever, but that history is important to the LBJ shelter and definitely affects their presence/relationships in the city!
Before Savannah became the shelter leader she wasn't very involved in the leadership / running of the library, which is something she resented a bit. She is a cery driven person and became a lawyer so she could affect change in the world, so being locked out by Gray was definitely a strain on their relationship. It's been 7 months since Gray died so she's been grieving but is also starting to become more herself again lately. She is pretty friendly and really values her relationships, so as HoH Savannah would value that friendship they have and take her advise seriously.