Override Category Functions in class_admin.php

I want to add extra fields to the store category page. I have made it work by directly modifying the CP/framework/class/class_admin.php file. However, I would like to override the functions:
my_category_fields() and wlt_update_icon_fields()

I tried doing do with the child theme’s function file but that doesn’t work and I found in another forum post that it’s not possible to override framework functions since the are not in the root directory of the theme.

I then looked at the CP/framework/class/class_hooks_filters.php file for a hook/filter that I could use but I didn’t find anything that looked appropriate.

I would like to avoid direct modifications to core files if possible to avoid overwrites with theme updates. Any other suggestions?