Create A-Z Filter for custom post type, and display a Thumbnail Grid

Hey, i was wondering if anyone could help me.
This is a Model Agencys Page, which has a huge problem with their Portfolio.

Situation right now: Models are being added as Portfolio Items (us_portfolio, themes own portfolio function), then they are added to specific Portfolio Categories (Men, A-Men,B-Men) and then these categories are being linked into a Menu which is displayed at the Top as the “A-Z” Filter. This is really Time consuming when adding a New Model.

What i was thinking when i found this plugin:
Create a custom filter, display the “us_portfolio” post_type with its Thumbnail and Post_Title underneath, just like the “portfolio” plugin does. This would speed up the page and the process, instead of reloading the page everytime someone clicks a letter.
I have kind of achieved this by using its built in Filter System for the Portfolios, but this is so confusing, as it will show the actual Portfolio_Category name, and not its slug in the backend when setting it up. (Meaning, if i want it to Show only letters, i would have to change all the category names, and i would have multiples for men / women, which i would never be able to keep apart. Thats why the Categories right now are A-Men, A-Women etc.)

Also, Can i only show specific post types inside that post_type ? e.g Men / Women

Hopefully, someone can help.

Bests,
Manuel

The page I need help with: [log in to see the link]