They climbed.....and I dun really know why only Tifa, Red XIII and Yuffie are limited to these CHI thingy you talking about and personally, I dun really know these CHI thingy did apply to the movie.
Just for References, you do know some of Cid's limit break specialize on jumping.
I told you all of them are equally strong through the game events and jumping from various structures to structures is pretty possible for everyone of them.
Before Cloud appear and fight Shin Bahamut, the others were
already fighting on the beams and structures. So it do explain they have ways to get that high and most probably they climbed.
Also. I dun really know why you said they jump higher than Cloud. They just merely appear at higher structures(They might have gotten into action first or start at a higher platform or jumped/climbed to that position to await Cloud.) than Cloud is and give him a hand while other jumped as to where Cloud's position is and gave him a push that's all.
It didn't really show anywhere that when two of them jumped together, Cloud jumped lower since Cloud make one straight jump while others could have jumped from platforms to platforms.
LET'S ANAYSIS.
After Cloud uses his Braver move or your so called Wuxia or CHI move whatever you think it is on Shin Bahamut, It crashes onto the ground preparing for an attack.
Look at his screenshot here, the group's head are looking up, so they must be in a platform pretty similar to where Shin Bahamut is.Take note that Barret
isn't in the screenshot.
http://img231.imageshack.us/img231/8446/1006lj.jpg
So Cloud make a leap and saw Barret awaiting him in a higher platform.Barret could have already on the higher platform before Cloud in the start.
http://i11.photobucket.com/albums/a1...nowns2/102.jpg
From this one, Cloud engaged Shin Bahamut but loses balance and started falling.
http://i11.photobucket.com/albums/a1...nowns2/103.jpg
Cid who appeared in the first screenshot, shows up in a
lower platform than where Cloud is and give him a push. Take note that this is
crucial since Cloud already wasted a lot of time this way and Shin Bahamut had already soar into the sky by now. This can apply to everyone else who will have jumped or climbed from platforms to platforms or such to a higher level than Cloud.
http://i11.photobucket.com/albums/a1...nowns2/104.jpg
And Red XIII leapted out and give Cloud a push.
http://i11.photobucket.com/albums/a1...nowns2/105.jpg
Followed by Yuffie.
http://i11.photobucket.com/albums/a1...nowns2/106.jpg
Take note that Vincent is already in a higher platform than Cloud is since he had enough time to get this high from Cloud's fall.
http://i11.photobucket.com/albums/a1...nowns2/107.jpg
And Tifa.
Aeris is irrelevant.
Didn't the game show how superhuman they are....like Cid can uses his limit break to jump high up into the air and Yuffie uses a big ball of energy against the enemies. Must they repeat all this in the movie to tell you? If you want to question it, you shouldn't question the movie but question the game instead.
Besides, all my characters are level 99 too.:D