I don't know who your legal advisor is, but I am shocked that a lawyer recommended this. (On a side note, dissolution is just a legal term for divorce.) Judges rarely approve full custody arrangements. For instance, it happens in cases where the child is in danger. Otherwise, they do not see it being in the best interest of the child. It's so hard to navigate a divorce, and I don't mean to be harsh, but you sound like every other naive client who has come back later asking for help. Would you trust yourself to give yourself medical treatment? Probably not. So why do you think you can easily navigate something that people spend 7 years of schooling and years of practice learning to do?

Another thing about narcissists is thay they lie. What if he shows up with a lawyer? What if he suddenly challenges the arrangement knowing he can lower his child support that way? As a matter of fact, did you know that he can petition the court any time to change your custody agreement, regardless of what decision is made now? What if he throws a fit about you living in another state? What if his parents choose to assert grandparents' rights? There are a lot of things that can pop up to hurt your case.

It sounds like he has gotten in your head, and I don't think things can be any worse if you get a lawyer. From a legal perspective, your current plan is very fragile. I know to you it seems solid, but again, that's why it's best to get help from someone who knows what to do.