Fairly certain it's true - it's the first time I've seen the actual letter, but I know that the signatories support BIP101.

1. I believe it's already been "priced in", and that it is, in part, the reason for the price stagnation over the past several weeks.

2. That depends on the outcome of the meeting! e.g. if the meeting finishes with no consensus, I'd view it as bearish. If the meeting ends with everyone hugging - well, that'd be bullish!

My opinion only, others may (will!) disagree, don't bet your house on anything I say!