In the example to which you refer, James omitted San Bernardino County because the reference was to an 1852 record when there was no county of that name. Had be been citing an 1854 record, his example might have been very different.

Was your g-g-grandmother Frauke Folkens who was said to have married Jan, the brother of her late husband? If so, you might like to explore the Junker Family Message Board on Ancestry.

"It sounds like ..." is not how a genealogist wants to hear a knowledge claim begin. Do you know where 19th century death records for Ogle County would be kept? Have you checked them? Was there a newspaper in Ogle Co in 1869? Did it report the news of the sudden death of a new immigrant?

Your list of three areas about which you are curious includes great motivation for exploring your family history, BUT they are not research questions. To proceed further you need to focus your efforts on questions for which you can find documentary evidence. A great start would be Where did Heert Heerts die? Until you can nail down a date and place, you have little hope of making progress on why he died.

Note also that this user has "prior form" and has chosen to ignore the advice that was offered then. Hence my vote to close.

From where did Richard Turkington travel to NY? Was he married at the time and did his wife travel with him? Have you found other information about Bessie Louden? Which parent died in 1851? (Or could it have been both?)