Record Usage and Interpretation

In 1890, Adolph Espe arrived at New York aboard the S.S. Slavonia from Hamburg. One column on the incoming passenger list (but not on the departing list out of Hamburg) is headed Death and Cause of Death. In that column, for Adolph, someone has written "6-4." Does this mean that he died on June 4th? Or something else? Six other people on the list have numbers in that column but the ink and the handwriting for those numbers doesn't match most entries on the page. I'm attaching an image.

I am looking at a 1870 census record for Daniel Dorris in New York City.

http://search.ancestry.com/iexec?htx=View&r=an&dbid=7163&iid=4274938_00619&fn=Daniel&ln=Dorris&st=r&ssrc=&pid=29910728

I'm using a collection of late 17th and early 18th New England merchant records. They did a lot of business with English and Scottish firms and I don't understand many of the terms in these records. Any suggestions for quick, online help?

A man dies 1780s in Virginia leaving a will in which the only specified property (land) went to five sons. No wife or daughters were mentioned, even though he had both. Within months of his death, the widow goes into court to "renounce her husband's will" and "claim her dower rights."  Question: how could she do this?  Is it the same thing as contesting  a will?  Could dower rights trump a legit will?

As an addenda to a question about citations (see "Descriptors in a citation and a question about Church Censuses"), Ann Gilchrist wrote:

Your QuickLesson 4 touches upon my problem. In the archives of my university, I found old photocopies of pages from several cases that deal with property destruction by the U.S. army during the Civil War. Each photocopy has a pencilled note that reads "French-American Claims Commission no. xxxxxxx, National Archives." I wrote the National Archives but they say I did not give them enough information for them to locate the cases among all their records. Can you help?