Which city does Qijia Ershe Qijiazhuang in Haifeng County, Wu Dingfu City belong to now?

It is "Wuding House" rather than "Wuding House". Historically, Wuding Prefecture had jurisdiction over northern Shandong and southern Hebei. Haifeng in the old days is now Wudi County, which belongs to Binzhou City, Shandong Province.

You can consult Wudi County Records or Haifeng County Records for your questions. The method is to register and log in official website of the National Digital Library, enter the search content under the column of Ancient Books-Local Records, and generally you can get the results in the volume of "Lishe".