Excellent essay Leolaia, Thank you for the time and effort you put in and sharing you research.
With regard to he official canon, I'm currently doing some research and this reminded me of something CT Russel wrote in Zions Watchtower July 1896: (highlight and underlining mine)
But, says one, you seem to take no notice of that remarkable passage so frequently quoted by our Faith Cure friends, "These signs shall follow them that believe, In my name shall they cast out devils; they shall speak with new tongues; they shall take up serpents; and if they drink any deadly thing it shall not hurt them; they shall lay hands on the sick and they shall recover."--Mark 16:17,18.
Yes, we are aware of this claim, but we have two objections to urge. First, neither observation nor history attests the fulfillment of such a statement. Of one thing we all have evidence; viz., that those signs do not now accompany belief in Christ. Nor is there evidence that they extended beyond the apostles' days and the time of the miraculous gifts. Even then, we have no record of all these things being fulfilled in all that believed.
Second, the oldest and most authentic Greek manuscripts (the Sinaitic and Vatican MSS.) do not contain these verses at all, but end at verse 8. It seems evident that Mark's gospel was originally incomplete and that some one undertook to finish it for him about the fifth century; for the Alexandrine MS., written in the fifth century is the oldest Greek MS. which contains the last twelve verses. Read these spurious verses carefully, note the marginal reading in the Revised Version, note their untruthfulness in the light of facts, and mark them in your Bible.
So it appears Paster Russell didn't hold to those untruthfull scriptures. However, the NWT does.
P.S. I think they're removed in the upcoming "Newer World Translation of the Holy Scriptures" 2007 (Patent Pending).
Steve.