I’m Irish and went to Uni in Dublin and it’s a great city. Ireland in general is friendly and sociable and you will make friends quickly if you’re open to it, there isn’t an ex pat culture for English speakers although there is probably an Americans in Ireland group of some sort and obviously Spanish/German/insert any other language speakers probably have their own networks etc but it’s so multicultural (perhaps not quite as much as London) with tons of English/Scots/NI people living, studying, sabbaticaling there that seeking out other English families would probably be considered a bit unusual!
Northside v Southside - well when I lived there it was a ‘thing’ a horrible, snobbish thing actually that was particularly perpetuated by Dublin families (particularly southsiders who wouldn’t dream of crossing the R. Liffey for anything because everything of any value was already on the southside and northsiders were absolute heathens) but it wasn’t something I was aware of for a while as I was in a melting pot of students from all over Ireland and the rest of the world and it was only when I had 2 Dublin friends, one northside and one southside get together that they were telling me how concerned the family of the southsider was 😂.
Traditionally, the ‘nicer’ leafier, wealthier (but often much more soulless) residential suburbs have been on the southside, with the more working class, less gentrified areas being on the northside. But these generalisations are out of date now, as ALL property in Dublin is at a premium and most of the really affordable inner city areas on the northside in Dublin where I mostly lived, are just as over priced as anywhere else.
Husband’s work being near airport means it’s sensible to focus on Northside for housing and the city being on the coast with beautiful coastline and seafronts/walks/beaches north and south means you will love it. Lots of great, more well adjusted areas to live on the southside but the posh areas are so ridiculously expensive that they are often quiet and depopulated as the homes are only temporarily occupied (richies having homes elsewhere). The Northside is typically more mixed and for my money, a bit more down to earth.
Schools - private is not necessarily better. At all. You would be best posting on Craicnet for better on the ground input on schools in the areas you are considering. But the Irish education system while not perfect, is of quite a high standard as teaching has always been a valued and respected profession and a traditionally safe employment destination offering family friendly hours etc so the cycle of highly educated graduates becoming teachers, generates well-educated school leavers, who are then attracted back into teaching etc etc. As someone else said above, the state schools are catholic faith based but it’s so diverse now, and Ireland having been monotheistic for so long, that Catholicism is not really very overt, it’s Christian ethos based in general rather than heavy heavy Church of Rome. There are lots of opportunities to get involved in school life, sports etc and your kids would be welcomed as much as any other child. Most Irish families aren’t particularly religious at all but just send their kids to the local schools and sports clubs because they are all usually pretty good and it’s where their friends are going.
There is definitely a snobbery between private schools in Dublin and from private towards state schools, but not so much between state schools and you’ll find the state schools bring parents “in” more which gives you an opportunity for getting involved and building connections whereas private will offer fewer opportunities to meet other parents/families.
Overall you’ll find the cost of living high and food prices high, but if coming from London you might find it’s a bit cheaper 😉
For accommodation, I recommend you try to find a house in an existing community/estate/development or within a good cluster of houses off a main road so that you and the kids can meet other neighbours and the kids can play safely outside etc. That’s the fastest way to integrate.