Finally got an email back, Party leader can't add them, each individual has to join the party themselves...
Wish they would let folks know when they change the process, and not do it midstream.
"We have opted to go back to the application process that we had previously, in that each party member would need to add themselves to your party instead of having to have to party leader complete all of the applications. Once you complete your application as party leader, simply give your party number to those individuals that you wish to add to your party, they will log into their own accounts and then select "Join A Party". At that time, the system will ask them for your party number. Your party number, should they all enter it, will be what links you all together.
If your party members are not able to add themselves, please don't hesitate to reach out and we'll be glad to assist in any way that we can."