"The bears are called Hans and Karl."
Translation:Die Bären heißen Hans und Karl.
Don't know if these are pet bears or if someone is insulting Hans and Karl.
Because that's the plural form. Why Insekten and not Insekte? It's the same. That's just what the plural is for these words.
The verb second rule in statements, does that apply to the 2nd element or word and is "Die Baren" treated as the first element to be followed by the 2nd the verb "HeiBen (no umlaut sorry) to follow the verb is 2nd rule
Scharfes s is not an umlaut – that's the two dots over a letter. ß is the same as ss and if you can't type the letter, you can use double s instead!
As for the question, I'm not sure I fully understand, but yes, absolutely, the article and noun are treated as one part. Surely you can't imagine something like "die heißen Bären". There have been so many sentences in exercises up to this point!