Midwives scrub for C-sections (or used to IIRC), as a children's nurse you could work as a theatre nurse in a large children's hospital, as an ODP you would be pretty much tied to theatres and nothing else (they do work in other environments, but this is very much in minority at the moment).
Now, as a midwife a large amount of your time will be spent looking after pregnant adult women. Either in the hospital or in the community, with a small amount of contact with babies during delivery and for the first few weeks of their lives.
As a children's nurse you could work with kids of any age, from newborns up to teenagers, in pretty much any clinical environment you can think of, especially if you have a large children's hospital nearby that your uni does placements at.
Tbh, from your post I'd suggest children's nursing, as it gets two out of the three things you're interested in, but in the end it's your decision, it's your career in the end.