#2 and #3 are true, not sure if they are a sign of death. As a (Danish) kid I found Norwegian (bokmål) far easier to read than Danish.
#4: I don't believe the ads are significant, and certainly not English street signs in areas a tourist may visit.
However, the last example is what Danish linguists consider the greatest threat to the language: Domain loss. Danish is really to small a language for specialized domains. When I write about my work, I use English, as the majority of people who might potentially be interested are from outside Denmark, and those Danes that might be interested can all read English. A generation ago similar texts would likely be in Danish, but a generation ago there was far less international collaboration.
[ Domain loss in Denmark is nothing new, Latin, French and German have all been dominating various domains earlier. The German dominance was far greater than English today, before the rise of nationalism Danish was merely a peasant language, and even for the peasants German words replaced Danish to a large degree. ]