I got no real answer for your first question. Maybe using a macro (via button) to export to excel. Or as a workaround your endusers can use "export..." instead of "send to excel". When using export they are able to chosse "xls" as filetype and an according filename.
For your second questions take a look into settings --> user prefs --> export-tab. Check "selection stamps on BIFF-Export" as biff is a rarely unknown name for the excel-format.
This is valid for both ways: "export..." or "send to excel"