I thank you for your posting and your generous info re: the IFHF database. I am not familiar with, nor am I registered on, this database; so I am very pleased to see your stats from and about the database.
As you found: the database's earliest listing of aJohn McQ* birth to a Wm McQ* being 1774, you have found my problem! I believe my John McQuaid to have immigrated with his parents to Lancaster County in eastern Pennsylvania between 1764 (the date found in Venango County, PA, histories) and a possible 1775 sailing of the Ship Prosperity on which is found one William McQuoid (a transcription).
Both a William McQuead and a John McQuaide have been found listed in Lancaster County units during the Revolutionary War. My John McQuaid was reported as "in his 89th year" when he died on 17 Jun 1850 in Venango County, indicating a possible 1762 birth in "Ireland."
Also, both family "legend" and what church records I've located for my direct McQuaid line show the probability of Protestant - possibly Presbyterian - ancestry, and therefore the very real possibility of Ulster origins. I've also discovered a veritible "nest" of McQua*s in the southern end of Co. Londonderry in the 1740 Protestant Householders lists for Co. Londonderry, including at least one household headed by a John and also a William. Of course, the problem is to connect any of those 1740 listings with my immigrant William and his eldest (known) son John in Pennsylvania.
Again, thank you for your generous sharing. Any other suggestions would be appreciated. I have registered with the IFHF, but the only listing for John ca 1762 seems to be a 1764 birth AND marriage for a John Wade in Dublin. I think it unlikely this would be my William and John.