I never tried to use the gobwalker as scholar so I don't know...
I would say no since it should be like a mount

But even if he drive it... If you have a SCH on full DPS it should easily make up for the DPS loss
Usually I as SCH DPS until phase 6 (first puppet)
And let the whm solo heal with EoS

...

And the drg should be able to DPS at the beginning... The end of p6 (before the 4 puppet)
And on the last wave...