August, Emma and Henry can all leave SB without the curse harming them. They are “in but not of” SB. Thus I doubt there’s a border at the Toll Bridge interfering with August’s movement. I’ve been thinking the curse that brings unhappy endings is strongest at the Toll Bridge and weakest at Granny’s B&B. So August had a moment of being “in and of” SB, falling under the curse — which he did not want to admit to himself or to Emma. Emma has the worst problem with falling under the curse – forgetting FTL entirely, doubting Henry’s book and spacing out her magical abilities.
In the new show intro, when the narrator asks who can break the curse, we are shown Emma, Henry and August. I suspect those three are family: mother, son and father. He’s so poetic about water because he was a fireman, and now feels how fluid and magical writing is. Once Emma remembers what Henry and August know about FTL and the curse, they will have the power to break the curse together.
I doubt August can be Baelfire or Pinocchio because then he would be trapped inside SB or could only escape into a limbo state like Jefferson/The Mad Hatter. I’m thinking his backstory in FTL begins after the curse is broken or he is only a baby in FTL like Emma when the curse took effect.