Just a few tips .
Since you guys will be doing the scripting yourself and will be learning as you go i would make a list of what is the lowest amount of content for a release meaning things like a recruiting new party member is not the most important while having the modules work and re-skinned with all the placeables and npcs along with the main quest working is the main focus. Once that's done you can add more layers of the new recruit option and other ideas expressed in your thread.
The reason you want to look at the lowest amount/level for a release is so you don't get bogged down with things that are cool and add something special but will add a good number of production time and take your focus off the main quest and getting it working.
Basically work on making the cake and not the icing.
I say this since many mods have started with icing and end up with nothing playable after a few months when they could have 2 modules ingame.
If you have any questions, let me know.