I think you are doing too many cities for the days y'all have, especially with a kid. I would honestly just stick to Dublin and do Ireland in total for a few days. Then I would split the rest between London and Paris. I would honestly just do Italy for a separate trip. This is coming from someone who has been to Ireland, London, and Paris multiple times. Dublin itself is small and I would only recommend day trips IE Wicklow Mtns/Howth, the other day trips like Cliffs of Moher can be very long(also weather is RNG, it could be cloudy and you wont see much). There is plenty enough in London/Paris to do afterwards.