I've been through the court process with my 3.8 year old. Developmentally she's closer to 3. Her dad wanted residency, then 50/50 but he was granted Every Other Weekend overnight and 1 afternoon a week for 3 hours.
The courts looked at everything including DDs developmental age, they also asked questions of her GP and other professionals involved with her to see who "does" everything. And decided that while DD needed contact with her dad, it was also important that she sees her primary carer every single day.
They even built up to her going away overnight. I had to let her go every Sunday for a period of weeks and then on I think the 8th week, she stayed overnight. We're still not at full overnights yet (10am Sat - 4pm Sun) and we've had this arrangement since end of January. It's going to take until just before we go for the very final hearing in April before he has her for a full weekend and even then under the arrangement I'll see her for a few hours either end of "his" weekends which I believe is best for her.
I was scared of the court process, but was surprised how I found it. It's not relaxing, but my solicitor did all the speaking for me and my views were considered at every opportunity. They were so kind to me when I got upset. They even let DD go and meet the judge and sit in the court room, which was cute!
The final hearing for me is finalizing the arrangements, and making sure that they work for everyone. I can't see them changing much.
Judges like the status quo, if you have been the child's primary carer (they have tests for this they don't just take you and your ex's word for it), then they will want to ensure young children see their primary carer every day.
And I doubt with a newborn it'll be more than a couple of hours every few days. The 2.5 year old might have to go overnight for 24 hours every other weekend but they'll be lots of preparation hopefully.