Can I suggest that you play her favourite songs, not look for “appropriate” songs. It will be a celebration of your Mum and you want people to smile, if possible, at her memorable songs.
I have told my kids that I want “Won’t get fooled again” the long version when they press the button on me.
Find out what Tom was singing when she threw her knickers, that’s number one, what’s her fav Buble that’s number two and I am sure Hugh has a mellow tune or two.
A humanist funeral is celebration for the people that remain.