You are welcome, and after you sort through and narrow down the specific records that can connect the dots and prove the relationship, forum researchers can help (if you wish). You can always post a new query for a particular search for a specific record and link to an old thread, such as this one, to supply the background details. Otherwise, when you've gathered so much information, it's cumbersome to re-post all of it each time you post a new query. Yet each new set of volunteer researchers will need to be brought up to speed with the information found-to-date.
Common sense suggests that William and Mary in the 1850 Wisconsin census are the parents to your David in California. After all, David's future wife is living quite near those parents in Wisconsin. The various records, taken together, would constitute a rather startling coincidence indeed if they were only coincidence.