Itsdarts,
I believe your question regarding the verses at the end of Mark is answered in your post. The quote says that some scholars believe that the questioned verses are non-marcon styled when compared to the previous literature in Mark. Therefore, it seems they might have been added. I'm not one to believe that the Bible's text is without error however, I do believe that it was when it was originally wrote. Also, Josh McDowell did an excellent job at comparing the present Old Testament text and some of the New Testament to the dead sea scrolls, and there was very little in the way of differences.
Visit this site.
Ancient NT Manuscripts
Also, regarding the ascension of Jesus. What about the latter texts involving Jesus' ascension? Acts 1:2, Acts 1:9, Acts 1:22 to name a few.