You have the most recent one.
After Norrin Radd released his HeroSelect programme, the NPC>27 Mod became a bit redundant as HeroSelect allows you to choose between lots of characters, which was the point of the NPC>27 Mod. So I never 'polished it up' or fixed the bugs.
The Mod was only ever a Beta (ie an unfinished prototype), and proof-of-concept.
It also had some inherent flaws (like no levelling up of selected NPC characters) that neither I nor anyone else ever found a fix for.
As for 'Most of the characters you select wont be swapped for your character and the skills will still remain the same as they were for the character that you just swapped out', it works for me, and pretty much everyone else who installs and uses it properly.
True, some of the characters don't work (about 4 or 5 out of about 40, IIRC, and these are mentioned in the README for the Mod), and others were very quick ports of XML2 characters which have since been done much better by other people as single Mods. Still others are just not that good, as I put it all together very quickly.
It's unlikely that I will fix any bugs. (This does not mean that I have 'abandoned' it, and its now in the public domain. Just so you know).