I have checked the 1852 census of the town of Hoya, but unfortunately there is no Mehlhop at all listed!
It might be possible that the family had left Hoya before 1852 or moved in after 1852, but I guess that the place of orgin/birth Hoya did not refer to the town Hoya but to the Amt (district) Hoya. We can find the Amt as the place of origin in many cases, namely for people from small villages.
The Mehlhop surname was and is quite common in the Hoya area and it is clearly concentrated there! The orgin of the name is quite clear as well: There is a single farm called Mehlhop which is located about 20 kilometers west of Hoya (part of the village community Affinghausen, Sudwalde parish, Amt Bruchhausen - but the Amt Hoya is just close by).
The Amt Hoya had 11 parishes - Hoya, Buecken, Eystrup, Hassel, Wechold, Eitzendorf, Magelsen, Oiste, Martfeld, Hoyerhagen and Asendorf. After the Sudwalde and Wietze parishes, possibly even Vilsen might be a chance as well this seems to be a great area to check, especially if you do not know exact birthdates and if there are some uncertaincies about the names.
Based on my family name databases* I would say (if the place(es) of birth were not Hoya itself, Asendorf, BÃ¼cken and Wechold would be the best chances.
* I found that the name appears (amongst other villages) in
Mehlhop, Engeln, Kampsheide, Warpe, Wechold and
Hassel. Your ancestors are not listed in the 1852 census
of Warpe (for which I have copies).
It would be possible to check the parish registers of these parishes (plus Hoya) or the census records. I can offer research assistance for both approaches, so if you are interested in a research plan and estimate, please contact me direcetely via my e-mail address.
If we would have the census records of all parishes above (which are all preserved for 1852 and all in one archive - the State Archive of Hannover) in a database it would take some minutes to find your ancestors - at least the most probable candidates. But right now we are (still) dependent on checking the orginal sources step by step, village by village and parish by parish.
Well, I am sorry that I am not able to come back with better news.
Best greetings from Germany,
HISTORICAL RESEARCH SERVICES, Germanywww.hist.de