I think I may have found Hugh McDonald on the 1871 census on scotlands people.
In the Abbey parish, there is a Hugh McDonald born Neilston aged 22 years listed as a farm servant. Unfortunately it does not help with the rest of the family.
To give you some idea of the geography - Neilston is a village within one mile of Barrhead, but in 1871 Barrhead would have been a very small area and part of Barrhead fell into Neilston parish and part fell into Abbey Parish. He is a servant in the farm called East???, Thomas Patterson, head of household, farmer of 32 acres.