Your welcome. I wasn't aware they didn't all have the same parents. I just called my mom to ask and she said she isn't sure but she didn't think Auntie Brenda and Auntie Donna have the same dad as my dad did. Again, i really don't know much about that side..i'm sorry i couldn't be of more help.
My brother Ryan (Doreen's son) is on fb tho, he probably has more contact with my dads side...mainly probably Auntie Carol. You could try messaging him on there and see if maybe he's more help, if he doesn't know anything im sure one of my Uncles or Auntie Carol must know where they are that he'd be able to ask one of them.