Yep, Christianity is filled with stuff like this and art. Most churches contain a decent amount of art. Most famous of all being the Sistine chapel, ofc. Found out this year about The Archbasilica of Saint John Lateran. Which is basically the Pope's main church. Always assumed it would be the one in Vatican, but no, it's a different one, in Rome. It's a very impressive place. Huge statues. This being the best. St Bart is said to have been skinned alive, hence the knife and his face.
I'd disagree, unless you want to say pop punk isn't punk (and if that's what you're saying, that's fair).
Stuff like this springs out of acts of popular piety. When you teach that the relics of people in heaven can work as prayer aides, it's a foregone conclusion that some may want to decorate (or even wallpaper, like the photos of the skulls) a prayer space with the highest class of relics.
This is how altars came to have a relic in a stone that the priest kisses at the beginning of every Mass.
It's an unanticipated but popular reaction to authority and came from the bottom up rather than top down, ergo pop punk.
Just because something is old enough to become mainstream doesn't mean it's not punk. Green Day. Blink 182, et al. started out being labeled as punk before the term pop punk became widespread.
I get where you are coming from. Skull Aesthetic can be used to represent both authority (Religion/govt) and rebellion (Pirates/Bandits), but Holy Relics only really rep one side of that equation. Your Pop-Punk blow works as a jab/word play. That said your label isn't actually Punk /s :).