When you gave the no answers, did they ask you for reasons. Think on your reasons if you did, and then you can see what other arguments they can now come up with. Object is to stay a step ahead. Think on all of your ex's, his wife's and their lawyers answers, now you may have new arguments yourself. Again the object is stay a step ahead.
As for headstart, obviously a court knows what that program is, so you have your arguments already as to the why's of this being good for the child. Just understand that there are people out there who have orders that the child is in 2 different daycares or 2 different preschools. It happens, and I'm not trying to scare you, just letting you know to prepare. My own opinion on it, nuts to order the child into 2 different daycares or preschools, but my opinion don't count.
I don't think anyone here sees you as out to get dad. Common when one is not in the picture to show up screaming 50/50, when one goes and files child support. They don't want to pay MOM/DAD(does occur when dad is the one with the child and files for CS to), they can't seem to get it through their heads, they are paying you back for what you spend to raise their child. Some never figure that out and some do. Men(no offense to men but)tend to not check into this prior, women usually check into it, his wife has an idea of what he will be paying, because she is a woman, lol.
If you have no trusted people for recommendations on lawyers, one good way if you have some time is sit in the courtroom that your case could be heard in. I have helped family members find some darn good ones this way. Another good thing on doing this, is you can hear cases and get a feel to what a Judge in your court might rule on different things. First though you would need to see if family cases in your court are open, I have no clue if that is the case in GA.
Yes if your ex gets angry and unreasonable in mediation or in a courtroom, that would help. Just saw that happen in case, and have seen it happen in others. Mediators can have opinions, it depends on how the mediation is set up. Here in my state they have binding mediation where it all will be submitted and what ever the mediator decides will be what the order is. They also have just mediation, where none of it matters, mediator does not have an opinion. Then we have some others that can do mediation and they write recommendations that most Judges will follow.
I don't know GA though, go back to the first page of this post, and the TheGeekess posted a nice list of links for you. Do some googling on mediation in GA, see if your court is online and if there is info on there, and check your site gov site to. Someone else might have a better answer for you to, but it sure will help you to read the links they left for you and to do some googling to.
Normally jurisdiction is the county the child lives in, but yeah you got a mess going with it. Honestly this is not something I can answer, not my strong suit when it is not my state, maybe someone else will have an answer for ya.