:::: Actually, I think you can do 1, 2, or all 3 in one step: 
 ::::* Delete revision text 
 ::::* Delete edit summary 
 ::::* Delete editor's username/IP 
 :::: My "Practice" with it (somewhere in my userspace) seemed to let me do any combination of them at will.  Although I'll admit, I haven't been "doing" RevDel out in WP space either. meh. / —