Is it possible? ofcourse.
Is it feasible for speed runs? heck no
The best make up for speed runs would be:
Warrior - Overpower (does damage compared to flash)
2 Bards - Wide Volley + Army's Paeon / Mage's Ballad
1 WHM - Holy

yes i prefer 2 bards over 1 bard + 1 blm.
really not even worried bout whm using holy either.
the only way blm would be better ... sleep