As Mariët -[in topic Re: Van Hees help!]- suggested to you : Ask your question at the prikbord of the 'Regionaal Historisch Centrum Limburg'. (just looked and spotted your question already there. Hopefully someone is thinking about it and doing a bit of research for you in the RHCL. Fingers crossed!). Or place your question in a forum specifically aimed at Limburg. At the moment - as others pointed out already- not much (yet?) available from this area and era via the internet.
Nicolaas van Hees [who married in 1767 in Grave] was a soldier; keep in mind that soldiers moved around a lot, not just for military actions but also moving from garrison to garrison. Perhaps the reason why your ancestor Nicolaas [from Heer near Maastricht] ended up in Grave, married in that [garrison] place in 1767 while he was actually at that time in garrison in Zutphen as noted in the marriage entry. Zutphen (in Gelderland) was a garrsion place as well.
It could well be that his father was a soldier too? Often more in one family were in the 'Staatse Leger'. Then you can expect children to be born in different (garrison) places. [I have a few soldiers in my research and found children born in Maastricht, Deventer, Breda etc. I could follow the families by knowing the Regiment they were in as noted in one of the the 'original' entries; the Regiment's name was not in the index on-line. Another reason I always prefer to see the 'original' entry!]
Not sure when you ancestor Nicolaas van Hees [born in Heer as noted in 1767 in Grave] left the army, but he is recorded as living in Grave at the time of his death on 17 October 1807; then 64 years old. Further noted that he lived with 3 children in Brakken Wijk B nr. 45. [Perhaps you will find this interesting reading:
http://www.milwiki.nl/milwiki/index.php?n=Onderzoek.Lezing-Wolters01a [put it into Google translate and use a bit of imagination when the translation does not make sense :)].
The parents of this Nicolaas could well be the Joannes van Hees and Elisabeta Maria Reijnart as suggested in your other topic. Was father [Joannes] perhaps also a soldier is a question that arises in my thoughts.
Can only find (in the GenDaLIm cd) two children born in Heer form this couple:
Baptism Heer 22-03-1744
Baptized child Nicolaus Vanhees
Father of the child Joannes Vanhees
Mother of the child Elisabeta Reijnarts
Sponsor Catharina Somers
Sponsor Gertrudis Rameckers (she could be the gr. mother of the child?)
Sponsor Nicolaus Vanhees (could be the gr. father or uncle?)
Baptism Heer 16-11-1746
Baptized child Fredericus Vanhees
Father of the child Joannes Vanhees
Mother of the child Elisabeta Reijnders
Sponsor Walterus Reijnders
Sponsor Josephus Van Hees (could be the uncle? brother of the father)
Sponsor Walburgis Duckarts
Sponsor Maria Berchems
I would try to search for more children; elsehwere? in garrison places? in Grave? Knowing the godparents at a baptism could lead you to finding and collating the family of grand-parents, uncles and aunties. With these two earlier baptisms in Heer as mentioned above (in 1744 and in 1746) there is already a good indication...
Now going back to the 3 baptisms in Grave in 1768, in 1771 and in 1777: Perhaps it was grandfather Joannes van Hees who was a sponsor at the baptism of Nicolaas' first-born son: Joannes Fredericus on 13-12-1768 in Grave. And the other godparent - Fredericus van Hees - at the baptism of Henricus Frederikus on in Grave on 01-12-1771 could well be an uncle of the child (brother of the father)?