Thanks for the replies folks. Always greatly appreciated!
In the hearth tax pages there is an Andrew Stewart at Drumburle , we discussed him eariler , but there is also an entry for a Hew Stewart miller at Milcawis. I'm assuming that is close to Drumburle and Cookiestoun. Probably an association with Andrew Stewart and son David.
There was a John Stewart at Cassillis Milne on the hearth tax and one nearby in Drumellan (yet to find it on the map). Neither of which are Maybole parish but are only a mile or so away.
The John Stewart taileyor of Minnibol from 1670/80's is not on the hearth tax list. could have died or just been skipped as GR2 mentioned. There is that Hew on the list in maybole town. The next Hugh Stewart in Maybole is the one having kids starting in 1718.
The first two baptisms listed are for James & William 22/07/1718. It doesn't say if they were born twins or just baptized on the same day later.
The latter Hugh Stewart was having kids at Crories Hill. When I look at the documents now in hindsight it all clicks.
Crories Hill = Crorus Hill
Corra Miln = Crorus Miln
Crorus , Corras , Coories , Cories , Curries
Looking on the Roy's map there was some kind of crofting site/mill at Crorus Hill. I went down the rabbit-hole of searching for "Corra" anything when it was right there the whole time...Crorus.
Hugh Stewart and Mary Egillshome had the boys William and James in 1718 and they must have died because they go on to have 2 more sons of the same names in 1731 and 1734. That son James in 1734 seems to be their last so they had kids from approx 1718 to 1734. What I believe to be Hugh's son John also at "Corra's Mill" born 05/08/1722 started having kids of his own there.
The first kid as mentioned was the unnamed out-of-wedlock child in 1740 with Agnes McKrenkine. He would have been 18 and her 16. Then he marrieds in 1746 and has son Hugh in 1747.
Anyhugh ... I can't say with any certainty that there is a connection between Hugh Stewart Crories Hill and the earlier Hew Stewart in Maybole on the hearth tax. More importantly I have little proof Quintin Stewart tailor is even related to these particular Maybole Stewarts.
I have to keep digging.

Attached: Snip of Hugh Stewart's last listed child Hugh in 1747.