In terms of general mediation, I am not a fan. If each side has the right lawyers you can get to the same place a lot cheaper without a mediator. I don't practice family law, but rather complex business disputes. A financial mediator just sits down and makes two columns. They assign time-values, etc. to the assets to make sure the parties are coming out as equal as possible.
I think if you have a straight-forward custody situation, which it sounds like, and there are not a lot of assets, and the spouse is reasonable, then your approach should be fine. If the spouse is disordered, or the custody is hairy (for example in my situation I have no problem with my D making her own decisions regarding seeing her father, meeting his friends, etc. but my S has some emotional issues that will make me fight to death to keep him away from H's home, friends, and family until after his 18th birthday), or there are significant assets, then you need more than what you are proposing.
Paralegals do not receive significant training, and unless the attorney overseeing them is actively engaged in the process and asking the right questions to ensure that the paralegal hasn't missed anything, then it can be a dangerous situation if there are any quirks to the case.
You know your situation and your spouse best. I am no fan of churning cash on any kind of case, but I do think working with a competent CPA and each of you having your own counsel (preferably ones that are trained collaboratively, though I wouldn't pay the costs associated with a collaborative divorce in a more straight-forward situation) can lead you to a fair, quick, and reasonable resolution. You might check the American College of Matrimonial Lawyers for someone in your area, or call your state bar and see if they offer a family law certification. What you want is someone who only does family law, isn't too recently out of school, isn't too old, and doesn't sell you on a senior partner overseeing a younger counsel (that's how you get billed to death while the junior usually handles the case).
Find a mid-range lawyer in a good, but not fancy firm, that takes a collaborative approach. My two best friends are divorce lawyers in different states. There are lots of these types of people in the practice area.
