Hello chenneefaulhaber we're facing this exact case at client side and actually what it's really happening is Option 1: User B overwrites the whole data region, NOT ONLY the cells he actually edited.
Moreover it seems that the "Edit mode" version in...
Thanks!
I'd add to the #1, the "Data Import - Flexible modification of source data settings for import jobs" functionality.
And waiting for some copy-paste_add multiple rows of data&values_import from excel functionality in a table.