Re Halloween, I was brought up Catholic, and All Saints Day (November 1st) was a Holy Day of Obligation, which meant that we would go to Mass. All Souls Day(November 2) was the day to pray for people you had loved who had died and probably go to Mass again to remember them.
Halloween was on the eve (i.e. the day before) All Hallows Day (i.e. All Saints Day). So there is nothing unChristian about that, in itself. It is part of the church calendar.
There are quite ancient traditions of handing out goodies like soulcakes, a sort of nice biscuit, to pay children for praying for your loved ones who had died, and this was the precursor I think of trick or treating.
We certainly didn't have trick or treating when I was a kid (and it wouldn't have been safe in our part of North London) but we did get taught loads about saints and Catholic views on the afterlife at school, and we went to church a lot, and my parents mourned the family members they had lost.
My own kids have got dressed up for Halloween, but not as anything involving skulls or blood as I wasn't comfortable with that. Pumpkins, cats and pirates, more like.