Class should be determined at the family level because people within families often depend on each other economically. The son of a wealthy family who works retail until he gets his inheritance isn't "Working Class", and his trophy-wife mom who signed a prenup and doesn't have a job isn't Lumpenproletarian either. The fact that they live together and support each other financially means their class should be considered at the group level.
As far as the Peasantry goes, the point I was making (and the point Marx makes) is that the Proletariat is unique in its revolutionary potential. There is a reason why we saw the rise of Socialism in the 1800s and not the 1200s, it's the development of the Proletariat as a class. Peasants certainly played a part in both the Russian and Chinese Revolutions, but neither of those revolutions would have happened without a strong, literate urban proletariat.
The Lumpenproletariat largely lacks the political literacy necessary to lead a true revolution. The only point where it may be possible is among people marginalized for their race, religion etc., like with the Black Panthers. The same factors that lead to drug addicts, criminals, and the mentally ill becoming lumpenized are the same ones that hamper their political literacy. But being Black doesn't inherently make it harder for a person to become politically educated, while it does make you more likely to be unemployed or seek out criminal or odd jobs due to systemic racism.
I know there are some islands that are disputed between Japan and China, were these ships in Japan's unambiguous territorial waters or in the disputed waters?