You can use the raceway as a EGC, but how many times have we seen broken/disconnected couplings, connectors. so i recommend to keep the #10 EGC.
however, how about if you drop the #14 and install one additional #12 and make it a MWBC. I did the quick math on the following:
.0211 x 4 = .0844
.0133 x 3 = .0399
total = .1243
This way you are still over but by only .0023"