A little, yes. :) olja comes through Latin from the Greek word from "olive tree". I don't know the etymology of Оля, though.
But speaking of which, that reminds me - did you know that Олга actually came with Swedes from the Old Norse name Helga? (And also Олег from Helge.)
They're generated automaitcally and course contributors have no control or say over them. Some are really, really bad - I've resorted to posting re-recordings that I've done myself in the forum comments for some 70-odd sentences. This specific word is perfectly fine, though - sounds exactly like many natives would say it.
Yes and no. The Swedish "the" is always a suffix, either -en/-n, -et/-t, or -na/-a/-en, depending on gender, number, and declension. If an attributive adjective is used with the definite noun, it also takes an additional article, either det, den, or de, also depending on gender and number.