GreyArea:
HT16K33...I’ve searched another thread where it says to use common cathode displays. Mine are CA. Not a huge thing to get new ones, but could someone confirm that I do actually need to?
That advice is probably for using 14 or 16-segment displays. Those are like 7-seg displays but have extra segments to display letters of the alphabet as well as digits. They will have more than 8 segment pins, so those have to be connected to the "row" pins, which means the digit pins have to be connected to the "com" pins. That forces the choice of common cathode.
You can (and I think must) stay with your common anode displays, because you have more than 8 digits, so your digit pins must can connect to the "row" pins and your segments to the "com" pins, forcing allowing the choice to be common anode displays.
EDIT: Actually, now I think about it, if you had purchased common cathode displays, it would also have been possible to connect them.