Hi and welcome to the Forum.
LOL - seems to be a thing with you Irish folk, the Emerald Isle calling you back home.
Assuming you are the birth father of your daughter, then you are both entitled to a UK passport (probably an Irish one as well). Assuming your wife only has Canadian citizenship then should you wish to return to the UK, then she will need some kind of visa. Yes, there is a lot of information online, I would recommend you use the UK Government website; this will take you straight to the start page where you can find out what kind of visa she needs and how to apply.
Perhaps an Irish passport for all of you would be easier, then you would all have the right to live anywhere in the UK and Ireland (in fact anywhere in the EU). It's certainly worth investigating.
With regards to your mixed marriage comment; racial/religious issues are still there; my opinion is that as long as you are careful where you live, you can avoid the excesses unless you chose to become involved in the flag-waving and drum beating. I served there in the '70s and when I went back as a civilian much later, I was surprised to still see the painted kerbstones and flags in front gardens, so it's still there.
Having a job to go to is almost a necessity for you to sponsor your wife for any kind of UK visa.
Hope this helps.
Cynic
Expat Team