As promised, I have reworked the original mockups for Dwarves and Trolls.
Wildhammer and Dark Iron Dwarves:
(tbh I am still rather uncertain about how to best handle allied races)
https://i.ibb.co/3442C6d/subrace-customization-mockup-wildhammer.jpg
https://i.ibb.co/s5Cx27W/subrace-customization-mockup-darkiron.jpg
Forest and Ice Trolls:
https://i.ibb.co/CtQ5FKP/subrace-customization-mockup-foresttroll.jpg
https://i.ibb.co/0YZtKJJ/subrace-customization-mockup-icetroll.jpg
May be a good idea to switch to these in the main post?