Is it possible to create a smart list of tracks that have had any changes made to them? Including adding tags, editing meta data, beatgrids, etc. Basically anything that’s been changed in lexicon?
Yes, use the Date Modified rule
That’s only if certain things are modified. It doesn’t take into account if tags are added.
Not sure what you mean, aren’t tags a thing? 
Do you mean custom tags?
Yes, if you change or add a custom tag, it doesn’t register as recently modified.
I’ll have to check that
Fixed in todays update