As you know this season has twins and there are a variety of twins throught out Big Brother verse
The first person can choose who the twins are and someone can take the other twin. :
Liz & Julia (cant choose anymore)
David & Greg (cant choose anymore)
Katie & Lucy (cant choose anymore)
Amy & Sally (cant choose anymore)
John & Edward (Taken)
Adria & Natalie (cant choose anymore)
Other than that choose anyone from bbus (s2-17) and bbcan(s1-3)