So, I've gotten a look at the newest unstable release now, and it features an all new customization option for the embarking hearthlings (that @Well mentioned above). Which also makes this mod more or less obsolete.
I'm not sure, though, how much further the team is going to take it, as I've not been following the progress that frequently recently. Are they going to extend it to also include the hearhlings that join the settlement later? Will they include an option to change the looks of a hearthling in-game?
If not, then there is no need to bury this mod just yet, I'll just have to make sure that this mod doesn't do anything for the embarking hearthlings, but instead changes the appearances (maybe even the characteristics) of those that join in later. That's what I'm going to assume also and work on the mod with that assumption in mid. But do let me know if I'm wrong in this, so that I know better what will happen later.