Good job mate, thanks.
You should look into other skins and look for the "ui_skin.json" and "skin.ini" files.
The first one (JSON) you specify the driver name, car number, team name and country. This then shows up in the sim. Just copy someone else json file and change the content.
The second file (skin.ini) you can specify what color/style of helmet, suit and gloves for the driver and pitcrew. And there is already many styles and colors to choose from if you look into "content/textures". As you can see in someone else skin.ini file you go into for example "driver_suit" folder and then choose from one there (plain, sparco, type1, type2), and inside each of them you have colors for them. So in the "skin.ini" you write for example (copy a skin.ini from another skin and just change the style/colors):
skin.ini
[driver_80] (this picks the 80's driver model. You can choose from different 3D models from "assettocorsa/content/drivers").
SUIT=\type2\white (this is from textures/driver_suit/type2/white. So you specify just the last 2 foldernames for each).
GLOVES=\ac_road\Red_black (do the same here and the rest below).
HELMET=\helmet_1985\white
[CREW]
SUIT=\type1\White_black (Pitcrew guy is in "assettocorsa/content/textures" as well).
HELMET=\white
BRAND=\porsche (this is the brandlogo on the "billboard" behind the pitcrew in the pit. There are 2 porsche ones to choose from for example. Look for "brand" folder in "assettocorsa/content/textures").
Sorry if you knew this. Just wanted to help out.