if the VLAN assigned to the ifgrp has no IP address set, then you can remove it. You wont be able to remove a VLAN with an IP address set.
What is the output of the command: ifgrp status vif-data10G
You have moved the ifgrp vif-data10G from default to the new space? Have you set an IP on this VLAN ? vif-data10-1504