If you want to do that I'd suggest you get 1 septdecilium elves that thousand to the power 17 í ½í¸‰
The second to last girl is 2 sexdecillion so I'm assuming the last one will not be more than 1 octdecillion (1000 to the 18th power) so if you have a septdecilium elves then you will be able to get them all at once.
I haven't been able to get them because I have stopped resetting a month ago and I don't have lin and Alice yet completely. Im pretty sure I could buy them but I haven't unlocked them. í ½í¸‚