Hello Richard and welcome to G2G. Yours is a good question.
When you are on the Profile page you will want to click the Edit tab (in the row of tabs). This will bring up the main Edit screen for that Profile and in the various fields for names you find: Last Name at Birth; Current Last Name; and Other Last Name(s). You can use the last category for the other spellings you describe. You MUST save the changes before leaving the edit page or it will default to what was there previously.
I hope this helps. Thank you for asking here.
~ Keith