Oh excellent
Was about to say I have a heap of errors from your file also but if you have found the resolution you should be ok to move things over to the official 5e Feats file (which will be functioning alot better than our was since we never finished it).
I learnt most of it just by looking at things in the editor. Feel free to pop into the GitHub and check out the Wiki, it has common code, etc. I basically update it every time i figure out how to do something since I am absolutely not a coder and rarely understand why something works.
I should make some videos on how to create basic stuff in the editor.