So here is her updated reference with a bit more detail.
Some details that I couldn't put on it because of the lack of space:

Her pendant is a Mirran symbol, it's in the Magic: the Gathering card game.
This is her usual, casual necklace.

The pink collar has a D-ring and her name on it in the form of that logo (I'm still not sure if it's easy to read but I like it, so I probably will keep it).
This collar has matching cuffs and can be used for some mild D/s play.

The metal collar has a hidden built-in locking mechanism. There are matching cuffs and even anklets for this set that she sometimes wears during summer in public, when her clothes aren't covering them - she just likes to see the strange reaction of the people, she thinks it's fun.
This collar is basically the same that can be ordered from the SM-Factory.

I tried to make some alternative hairstyles too, but the main is the one on the headshot with the pigtails.