You CAN edit and copy a career CAF(stop buying boosters!!)
(Credit goes to 'Thisisnotanexit' from MMA-CAF.com)
Load your retired career fighter. Edit something of his (I edited his fighting out of in basic information). Overwrite save.
Load up that fighter again, he should NOT be under retired fighters. Go to show all CAfs. He'll be listed as a "retired fighters". Fighter Abilities should still NOT be available. Go to finish and create NEW SAVE. (note you dont have to edit anything)
That new CAF should now be a listed as a "CAF Mode CAF". Load him up now. Completely editable. You can redistribute stats/attributes and technique. He'll only have 12000 technique points available TOTAL (minus whatever moves your career caf had, you can edit them). You can edit name/weightclass/etc etc.
OP's Note: THQ is well aware of this and are working on a patch. Preparing for a worst case scenario, you should create many new saves of your Career CAF/CAF mode CAF
To switch Weightclass WITHOUT resetting Attributes:
Immediately after turning your retired CAF into a CAF mode CAF, goto weight class and change it. Note the weightclass limits as if they force one of your ratings down, you will lose the points.
Also, its a good idea to Ignore all technique training and focus solely on training games and gaining as much Cred as possible. This way you can have the points you need to make fighters rated upwards of 95. as Thisisnot wrote, you'll automatically have enough technique points(12000) when you finish the workaround and start editing him