GH:
Not so fast about custody. NYS law, for instance, disallows arbitration agreements regarding custody, and every BD knows that. Batei din might make recommendations, but these have zero legal standing. There are other features to divorce agreements relating to children that can be argued to be considered part of custody. These become issues when the couple proceeds in BD and these issues are put on the table. The matter is not simple.
The Get Law in NYS was rewritten, with its first version having been thrown out by court as a violation of church-state. There are even poskim who consider today’s version an automatic “get me’usah” and will not perform a second marriage to any woman that has a get/divorce in NYS. Radical but reality. Nothing is simple in this arena.