thanks for your feedback. The 5.0 is currently still under development and there are still some issues left open, because we are in the process of migrating to the new GUI technology.
I cannot confirm the second issue on Windows 10. When I doubleclick on an entry in the column I explictily have to click in the author field to modify it.
But if you selected it once, the author field will still have the focus if you change the entry.
However, if you click again in the table on the entry the focus is no longer in the author field.
The 3rd issue:
Already possible: Either you press CTRL+G or you click on the key-icon in the left bar.
The 4th issue:
The filename is created using a pattern you can define in the options under Import, you can there also define a pattern for a folder. The pattern follows the same as the bibtexkeypattern: