I've been wondering if it is possible to create a script that lets the player create characters that they can add to their party. It doesn't have to be very complex or anything. But if you could have like 5 of each option (hair, shirt, pants, etc...) that would be great.

How script savvy are you? I mean, how much do you know about using them?

There are two scripts you may be interested in using, and then use it for the basis for an editor:
1) Visual Equipment by Me™ --- To apply the hair/eyes/etc graphics to a characterset
2) MultiSlots by DerVVulfman --- It is a system that allows you to have additional armor slots, even hidden slots.

The key is this. Visual Equipment can place additional graphics on your character based on what weapons or armor you are carrying, like it will draw a helmet on your head if you have a helmet equipped. And MultiSlots by DerVVulfman has the ability to have 'hidden' slots so you can make slots (like eyes/hair) that the player cannot see nor alter.

Use the two together by making a third 'shell' script that allows you to choose your eyes, hair nose, beak, etc... These items are 'equipped' (thanks to MultiSlots) into hidden slots for each character. And then Visual Equipment will find that equipment/body parts and draw them.

Some time ago, I promised to make a script like this. I forgot about it. I will try to do it now.