Lee, I believe that McQuade is a different family and is not considered one of the spellings for the original McCuaig/McQuaig/McQuaige/McQuage/McQuague/McQuagge family.

"The name MacCuaig is a variation of MacDhubhaig. In the Gaelic pronunciation MacDhubbaig is the same as MacCuaig; only the C in the later is more stressed, hence to a Gaelic speaker the change of spelling is easily understood." The English transcribers always had to put a Q in front of the U and thus the change when transcribed into English.

Thanks for the info on James C. McQuade.