PeopleHR and Paycircle need to link and share data before going Live

Having populated People HR I find it odd that I need to wait until everything is live before it starts talking to Paycircle. PeopleHR is the one truth and it will introduce errors if I have to re add the same data into paycircle. I can't go live in paycircle until everyone is in and everyone won't be in untill it goes live..