What ever Happened to Wilhelmina?

In the search for information on my Great Grandmother Bertha Belitz Lucht I've found her mother Wilhelmina, a sister Lousia and brother Frank have done a disappearing act.

Here's the story:

My Great Grandmother Bertha died and was buried in the Muskego, WI Cemetery in July 1900. To make way for an amusement park in the 1950's the graves were moved to a mass grave located in Highland Cemetery located in New Berlin, WI.

In the process of tracking down her grave I noticed two people with the same last name listed in the records for the moved cemetery. Frederick Belitz has a birth and death date listed but his wife Wilhelmina didn't have either, just her name. This reminded me of my mother's headstone with my father's name but with no dates as he hadn't yet died when she was buried. Could this be the case with Wilhelmina?

I know Fred and Wilhelmina are Bertha's parents because Fred shows up on her marriage information and Bertha's husband Herman is listed on Bertha's aunt, Dora Peters will. The family is listed in the 1860 census with Fred, Mina and 3 children; a boy and two girls: Frank, Lezarette and Louisa.  My Great Grandmother Bertha isn't included since she was born in 1861.

In 1865 there should now be 2 males, Fred and son Frank. And there should be 4 females, Wilhelmina and daughters, Lezarette, Lousia and Bertha, but there's only 2 females counted. So what happened to 2 of the females?  An aunt, Dora Peters lives at a residence farther down the census so I know she's not one of the females. I know Bertha is alive in 1865 since she goes on to marry and give birth to my Grandmother, and I know she dies in 1900. I also know Lezarette is alive as I've found her marriage in 1875 and death information from 1914.   On a later US census' Fred lists widower in the marriage column, so I know Wilhelmina has died before him so that rules out that she was still alive at Fred's death.

In the 1870 census Fred now lives with his sister Dora Peters. I believe Bertha is possibly living with a brother of  Fred's since there is a Bertha Belitz that is the right age living with a Carl Belitz in the same area. Lezarette Belitz lives with another family as a servant. Frank is gone, so he either died between 1865 and 1870 or possibly went to fight in the Civil War as I have not found anything after the 1865 census.

A distant relative had a Rootsweb post assuming Wilhelmina ran off taking Bertha with her since a later  census  has a mother/daughter named Wilhelmina and  Bertha living in a near by town. Which might make sense if Fred didn't have  Wilhelmina's name on his headstone and Bertha and Lezarette  didn't marry men from the same area where they continued to live and raise families. And why would Wilhelmina only take Bertha but leave the son and two other daughters?  

I think Wilhelmina and the other daughter, Louisa died sometime between when Bertha was born in 1861 and the 1865 WI census. This would account for the 2 males and 2 females in the 1865 census. So I searched cemeteries in nearby towns using findagrave.com.   I did find Lezarette (who has changed her name to Elizabeth) but still no sign of Wilhelmina or Louisa.

I've also checked the courthouse but records don't go back that far. 

My thought is in looking at findagrave there are a few cemeteries that were destroyed and have no records of the graves that were located there. A few cemeteries are now on private property and also have no grave records. I think Wilhelmina and Louisa were buried in one of these cemeteries. Possible when Fred died the family had hopes of  having Wilhelmina's body moved so they could be together but either it cost to much, they couldn't find her grave, or just never got around to it since my Great Grandmother Bertha died shortly after Fred.

Hopefully sometime in the future it will all come together but in the meantime I'll keep looking for the rest of the family.