Many thanks! I got Calendars 5 and it seems to cover the bases. Re: Item #3
But, could you please explain this part of your response?
Thanks!
Notifications or content comes to your phone (or computer or whatever) through one of two ways: push and polling (sometimes might be referred to as pulling or fetch). Polling is when your app or device or whatever checks a server for information at set intervals, so like every hour or 15 minutes or even manually. Push is when a server pings you with a notification or sends content to you when that stuff is updated on the server.
So for example, email. Without push, iOS has 4 fetch/poll settings for the Mail app (and Calendar app and Contacts app): every 15 min, every 30 min, hourly, or manually. That means any new emails that come into your email account will only be received in the Mail app at those times (though you can manually trigger a refresh whenever if you're in the Mail app). With push, when a new email comes in, the server sends that email to your iPhone immediately. Obviously if your app or the device is polling more frequently, you're using more battery life because your phone is constantly doing something.
Push isn't something you can enable with everything. Google used to support it on iPhone with their calendar, contacts, and Gmail services, but they dropped support for it a few years back.
So what I meant by push not working is that because you might be using Calendars 5 with the Local Calendars functionality, Calendars 5 isn't interacting directly with Google's servers. It's getting calendar data that iOS pulled from Google's servers. I'm not sure if apps can force iOS to manually refresh calendar data (and contacts and email data).