After checking SSEEdit for any overwriting to the keywords (I was testing it with other mods installed), I found that nothing was affecting the location keywords. However, when I started a new game, despiting changing absolutely nothing, it curiously started working.
I know some mods require a new save or updated cell in order to work. Any idea if that is what happened here, or should I just chalk it up as a quirk of Bethesda games?
Either way its good that its now working, but if there's something to learn from its initial failure, that'd be helpful for the future. I suppose I could suck it up and uninstall all my mods before testing a new mod also.
Edit: After some testing, it seems that new games with the mod, new games without the mod, and previous saves that have never seen the mod before all work correctly when the mod is activated. The only saves that don't are saves that used the mod in a previous version. I'm thinking something about the previous versions of the script are left behind as I update it and cause it to not operate with updates I give the script. I'm not sure if this happens with all script updates or just keyword related ones, but apparently I'll need to watch out for old scripts not operating on their updated versions from now on.