Cofty this is a good letter! I agree about removing the "red pill" reference, which will confuse those of my generation. I also agree with black sheep that what you can't support with references to the WT's public written statements will hurt credibility. Here are some proof reading checks:
"Reverend Knox sent the planning committee"
"Arian Controversy" -- most people will not know what this means, and many don't care. Either describe it briefly -- for example, "Arian Controversy (denial that Christ is divine)" -- or leave this part out, if you think it distracts too much from your main topic.
"but don’t mistake cordiality for friendship", or "but don’t confuse cordiality with friendship" (a minor difference, I agree, but attention to detail bolsters your credibility)