[Part Two]
There were several Johns living there at the same time as Robert, as each of the Hughs had a son called John. Given the names of their children, (around this time a Highland tradition of naming the first born after the grandparents, then the parents, and then the siblings and friends, became very popular, as can be seen with Robert's family above), I think John, the son of Hugh senior and brother of Robert, born 1746, married Mary Fisher, the daughter of Patrick Fisher and Christian Mclaren, born 1756;
1778 John McGregor married Mary Fisher [both Balquhidder parish]
1779 John McGregor/Mary Fisher daughter Janet Auchtoumore Balquhidder
1780 John McGregor/Mary Fisher daughter Christian Auchtaramore Balquhidder
1782 John McGregor/Mary Fisher son Hugh Easter Auchtowhead Balquhidder
1785 John McGregor/Mary Fisher daughter Margaret Achtoumore Balquhidder
1786 John McGregor/Mary Fisher daughter Jean Auchlarmore Balquhidder
1789 John McGregor/Mary Fisher son Patrick Auchtumore Balquhidder
1793 John McGregor/Mary Fisher daughter Bettridge Auchtowmore Balquhidder
1795 John McGregor/Mary Fisher daughter Mary Achtumore Balquhidder
1797 John McGregor/Mary Fisher daughter Kathrine Liascridan Balquhidder
1800 John McGregor [lately deceased]/Mary Fisher daughter Joanna Lidenscridan Balquhidder
John the son of Hugh junior, born 1757, is probably this family;
1790 John McGregor of Auchtumore married Janet McGregor of Ruscachan
1791 John McGregor/Janet McGregor son Hugh Auchtoomore Balquhidder
1792 John McGregor/Janet McGregor son Patrick Innerviach Balquhidder
1793 John McGregor/Janet McGregor son Peter Inneriach Balquhidder
John the son of Hugh ban, born 1764, and Janet the daughter of Robert, born 1777, is probably this family, (based on their children's names, and for Janet the census records and her sisters' death certificates);
1798 John McGregor married Janet McGregor [clandestine marriage]
1800 John McGregor/Janet McGregor daughter Janet Easter Achtu Balquhidder
1802 John McGregor/Janet McGregor son Hugh Easter Achtu Balquhidder
1804 John McGregor/Janet McGregor son John Easter Achtu Balquhidder
1807 John McGregor/Janet McGregor son Robert Middle Achtu Balquhidder
1810 John McGregor/Janet McGregor daughter Janet Middle Achtou Balquhidder
1813 John McGregor/Janet McGregor daughter Margaret Achtu Balquhidder
1819 John McGregor/Janet McGregor son Duncan Auchleskine Balquhidder
If you're interested, I collated the records from here;
http://www.clangregor.com/parish-records/balquhidder-parish-baptisms/