I think I have an answer about the word 'college' in the name of the school.

The following information is far from official :)

Well, when the school was founded in 1860, Bulgaria was under Turkish yoke. Because of that two languages were spoken: Bulgarian and Turkish. But the western culture was entering slowly in Bulgaria and French language and not English was spoken all over the country from the intelligence. In the French language there are two words for high school - college and elysee (with some stresses). The word college is used for high school as well as secondary school. It is pronounced [kole:g].
When I was sixth grade I was participating in a French theatre contest and the name of my secondary school was written as college, but what I noticed is that the contesters' school from high schools was written as college too.
So the name of the American college is named as it is French, because of the western French culture when it was founded.