Not sure how others have done it, but the foilcals look like they could be maybe removed using the car emblem shave trick. Heat and or goo b gone and some dental floss to slide under the foilcal and slowly cut away the bond.

Never done it on a speaker and dunno if it'd work, but it's worth checking a video on YouTube for inspiration.

Looking forward to see your solutions to what you're faced with. Trust these are gonna look great.