On image 485 Familysearch
you find the marriage
Harmen Wesseling jm van Osnabrugge en Vrouwtie Sieuwes jd uijt Vriesland
29 juni 1749
Luthers trouwboek
So - Evert might be their father - search also the baptist of Hermen
No luck finding Harmen/Herman's baptism in the Gehrde records.
A couple of other things.
First, since we're going on naming patterns, among the children Jan Hoenderdos and Catharina Wesseling had were:
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4 M:
Jurriaan HOENDERDOS
Christen Date: 8 Jan 1775
Christen Place: Haarlem, Noord Holland, Netherlands
Witnesses: Johannes Rudolph SEGELKE and Petronella DORICK.
Religion: Evangelisch Lutherse
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6 M:
Evert HOENDERDOS
Christen Date: 9 May 1779
Christen Place: Haarlem, Noord Holland, Netherlands
Witness: Maria VALK.
Religion: Evangelisch Lutherse
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According to Artland Resource Collection for History [ ARCH ], transcriptie Collectie Pohlsander 030, page 14 was the following overview:
Evert Wesling, * ca 1684 Gehrde, begraven 19.2.1754 Gehrde, 70 J., zn.v. Jürgen Wessling en Trine Eilermann, 1713 Gehrde, Anna Statmann, * ca 1673, begraven 11.2.1725 Gehrde, 52 J, Kind.;/
Jürgen, ~ 13.5.1714 Gehrde./ Catharina Elsabein, ~ 4 Advent 1715 Gehrde, ┼ 10.3.1758, 43 J., begraven 12.3.1758, 27.7.1736 Gehrde, Johann Evert Thelkamp.
For more, please see here:
https://arch.vortmes.nl/documents/copo-030.pdf
It's possible Harmen/Herman's baptism wasn't recorded? Or it was recorded elsewhere? Also, couldn't find Harmen/Herman in the Lidmatenboek of Haarlem.