Hey there and thanks for getting in touch!
Say the time of the event was changed, do I need to delete and re-import?
Not at all. In fact, iCal Importer will ask you if you want to import a previously imported event and, if so, that will import the new information.
A) Is there a way to update more frequently than 30 minutes?
Sorry, I’m afraid not unless you do the import manually.
B) Is there a documented way to achieve the color coding you can do in Google Calendar?
There is a free add-on for The Events Calendar that adds color coding, called Category Colors. I would suggest looking into that–though please do note that it will not import the actual colors of the categories from Google Calendar.
Does this help answer your questions? Please let me know. 🙂
Cheers,
Geoff