Losingit asks "Do they get anything right?" as I have said before, my default position is, " if the WT says it, it is probably wrong."
Certainly from my examination, all of their unique teachings and practices are wrong. ( I am not referring to things they do not teach Immortal Soul,Trinity etc).
The Memorial as they practice it is wrong on so many levels, not least because they make it such a sombre , gloomy occasion.
As to the point you make Jeffro, that Jesus was iniataiting an event "in place of the Passover", I do not quite see the reasoning for that, surely the Jewish Christians, including Paul, long after Jesus death continued to celebrate Passover ?
As to considering it a replacement for Passover, that gentiles could celebrate on its own, no doubt that happened, and more than likely they would do it, if they were only doing it once a year, at the time the Lamb was either slaughtered (preperation day), or sacrificed (perhaps more likely), which events occur on different ,consecutive, days, which again puts Nisan 14 in doubt. Not that the WT can even get Nisan 14 right as you ably show.