We live in a data age. There is NO REASON something like this should not be implemented.
Colorado should put itself out there as a model to follow. It took a while to work out all the bugs, but it has been in place for many years now, and I consider it both convenient and effective.
We even have a process whereby you get an email when your mail-in ballot is received (whether it is actually mailed, or dropped in one of the hundreds of secure drop-off locations.) And another when it is processed – and even notification if it was rejected for some reason.
Colorado drops your voter registration if you haven’t voted in x-many years. (I think it’s 10.) Thinking behind that is to clear off people who have moved out of state. Your item #1 above would fix that.
But if you get dropped, you get a notification mailed to you telling you of that action, and telling you how to reinstate if you were dropped in error.
There are students who set up permanent residence in that location. Let them vote where their permanent residence is. (Which means getting a drivers license in that state. And registering to vote in that state. Etc. It impacts more than just voting. State (and in some locations, county) of residence also impacts things like state income taxes, for example.
Colorado mail-in rules dictate that the ballots have to be RECEIVED by close of polls on election day. News and PSA announcements flood the local info streams telling people when the last reasonable day is to mail in the ballots so that they are received in time. But you can drop the ballots at one of the hundreds of drop-off boxes, and as long as they are dropped by 7PM on election day.
As long as the rules are clear, it’s not unreasonable to expect all votes be in the pipeline by a given date/time. (Overseas ballots are a different matter. Especially military, since there is an additional handling process involved.)
Extending the window for countable votes just leaves close races unresolved for too long, in my opinion. Nonetheless, I could still live with a longer horizon if that’s what’s ultimately implemented. I just wouldn’t like it as much.