The coding observations are actually informed choices... nwn2 doesnt support arrays (trying to replicate them makes them more expensive juryrigged things) ... reading everything from 2da files is significantly slower and more expensive than the copy paste method and is prone to causing TMI errors . For singleplay this isnt an issue but with multi efficiency matters. when i compared it it did better than than the original mechanic.
The spell swapping is an oversight on my part. I thought you were allowed to switch lower invocations out for higher ones. Because you can freely pick to start with.
Luck of heroes sounds like its something screwed up in the training module. That feat wasnt touched for any content that I remember.
Casterlevel is also set in the spell hook and most feats are treated there. Including psc if memory serves... that feat shluldnt give spell progression.