Thanks for the reply.
I actually went to a kiosk today and was told I can add more lines. Apparently the limit is related to how many devices, but since all of my 6 current lines are BYOP I can apparently add more lines.
I didn’t actually add the lines though since I didn’t have the people transferring their lines with me.
So are you sure the maximum lines is 6. The kiosk person was just mistaken? I guess I’ll know for sure when I go with everyone and they try and actually add the lines.