Once I found the birth registrations for the Morren children naming their mother as Lubbertje Aalts Hop, I had to resolve this conflict. Up 'til then, I had named Neeltje Dekker as the mother. After all, she is named in the list of the family in the North Holland Church register, census records and she is buried beside Willem Morren. SO next up was a search of the marriage registers.
Here is the marriage certificate of Willem Morren and Lubbertje Aalts Hop.
What this says is (briefly) that on the 19th of January 1848, Willem Morren, bachelor, age 24, farmer, born in Ermelo, living in Harderwijk, son of Jan Morren and Cornelia van Welsum
and Lubbertje Aalts Hop, maiden, age 24, no occupation, born and living in Harderwijk, daughter of Aalt Lubbertsen Hop and Petertje Willems, both deceased
were married, having filed the following papers: certificate of groom's military service, extract of the groom's birth record, extract of the bride's birth record, and extracts of the death certificates of both of the bride's parents. (That last part I cropped off)
Next to find was if there was a death certificate for Lubbertje Hop. And, for sure, it was there.
It starts out with a staement of who is making the report of death and then states that on Wednesday the 26th of December 1860, Lubbertjen Hop, wife of Willem Morren, born and resident of Harderwijk, daughter of Aalt Lubertsen Hop and his wife Petertje Willems, died at the age of 36.
Thanks to all the detail in these records, it is easy to see that they are talking about the same person.
Just to put the final piece in place, I next found a marriage record for Willem Morren and Neeltje Dekker. I don't have the certificate scanned, but here is the online extract of the marriage: