The information you read is correct.
However to obtain said mount is a " Nightmare "

Look.. best advise i can give you is Que up for Garuda EX mode since it's the 1st that becomes available in the new Story line quest.

Practice , Practice , Practice. > in the event that the STARS align just right and you actually win using a PUG from DF ... you will have the option to /roll on the MOUNT
as it is available for winning the fight.

That said you got a 1/7 chance of winning... GL

If your in a FC.. then discuss among them to find a group that is willing to put in about 8 hours .. grind to farm these for each member. The 8 hours is an average of 1 hour for each member.