These are all excellent questions, Daba, and I think it's great that you're thinking through the issues before your child is born.
Your lawyer is right: it's best if parents can work out custody, guardianship and access issues between yourselves, if you can. And, in my view, it's best if these issues are settled through an agreement that addresses all of them. Most of the issues you're mentioned have to do with access, but ultimately issues of custody and guardianship will have to be settled, too.
You're also right that newborns have different needs than older children. Have a look over
this helpful website that discusses parenting after separation, and (about half way down) outlines some general parenting time suggestions for various ages, for parents who do not want equal time. The guidelines here come from a terrific book called "Helping your Kids Cope with Divorce the Sandcastles Way".
I think it's appropriate for you to have clear boundaries about his access visits -- it's quite normal that visits are the responsibility of the visiting parent and are usually conducted outside the home.