1) This is possible, but it may not be as intuitive as you'd like. The approach used depends on the workbook/data. I've seen parameters used to enable various sorting, etc. but there may also be a simple solution--I would need a workbook to provide any specific advice.
2) To sort by year, go to your data window, right click and choose "Default Properties">>"Sort" and change the default sort order (I haven't tested this, but believe it will resolve this).
3) The area where ABCs shows up is known as the "pane", or where you place things on the "Text" (AKA "Details") shelf. To hide it, you can simply slide the pane over--if you don't like that look, you can create a calculated field called BLANK with a calculation of an empty string (''), and place that on the Text/Details shelf. This will put blank space where the ABCs are.
More info here: Removing "Abc" Placeholder Text | Tableau Software
4) Yes, but again, a lot depends on the data and there may be various approaches.
If you need more help, I'd suggest posting a packaged workbook with some sample data that represents your situation, as well as a clear description of the end-result you would like (or a mock up)
I hope this helps get you started. Cheers.
Didn't realize that you had uploaded a Tableau Public workbook. For #2, you can simply use the sort icon on the Year header to sort in descending order. See attached for that.
Donations Listing ML.twbx 76.2 KB