[Question] Is it currently possible to modify NPC avatar appearance/behavior?

[TelluriumCrystal]

I limited experience in game modding but I am familiar with programming (ECE student, I mostly do microcontroller stuff in C).

My question is how much of the NPC avatar code is moddable. For instance could I change the clothes a specific person is wearing, or could I alter how and when they move around stations and ships? There are a lot of things that currently bug me about NPC behavior and if this is possible then I am definitely going to get into modding to try and improve it. I just don't want to dump a bunch of time on something that is known not to be possible, and this being a newer feature for the X series I am suspicious it isn't.