First of all, a language matter:"Hannover" is simply German for "Hanover", just like "Deutschland" is German for "Germany".
Just like the U.S., Germany, too, has always been made up of STATES.Hanover was a STATE covering an area about the same as that covered by the U.S. states of Maryland and Delaware combined.So you won't be able to proceed until you do further research and find out exactly which city, town, or village in the state of Hanover these people were from.
And nobody here would be able to help you anyway until you provide a time frame.You gave absolutely no indication whatsoever as to WHEN these relatives lived!Did they live 75 years ago? 100 years ago? 125 years ago? 150 years ago?
And because it just so happens that all the names you mention are such common names in Germany, you're going to have to be in general a lot more specific about these people.