כּ, "kaf" with the "dot" in the middle and a "k" sound, usually appears at the beginning of a word. כ, "chaf", which is pronounced "ch" like in "loch" or the German word "ach", appears in the middle of words. ך is "final chaf" or "chaf sofit" and appears only as the final letter of a word. The sound is transliterated as either "ch" or "kh". I prefer "ch" because that spelling appears as a sound in words like "loch" and "Bach, ach, ich" that many people are already familiar with.
Yes, but it can be very frustrating. I hope that when the course comes out of beta they are able to have the slowed down pronunciations like they do in other courses. I also find that having the pronunciations that are difficult to understand at first can lead to a misunderstanding of the correct pronunciations.
Because א is not a vowel but a consonant. Hebrew script is an abjad, not an alphabet, in the sense that it lacks vowels. However, in order to avoid ambiguous reading, א ,י ,ה ,ו can also be used to indicate a vowel. When א is used to indicate a vowel, it's usually /a/, but not always. In this case it is pronounced /o/.
Please take a screenshot. I am suspecting though that maybe you were not supposed to translate for the exercise that you had. Perhaps you were supposed to listen and write it down, but, then they show you the translation anyway in case you want to know, even though the answer was the original sentence. Did they really use the words "correct answer" ?