@kpare - A) I believe Rachio does pull from CWOP so you can continue to use your weatherlink. The Aeris (http://support.rachio.com/article/250-weather-service-faq) network they use pulls from a couple of sources- NWS, CWOP, PWSWeather, etc.
B) See -> Using WUnderground.com to integrate Personal Weather Stations for a quick and easy way to get data from WeatherUnderground to PWSWeather. Start around post 128 and look for @Gene.
C) Who knows what @Franz has up his sleeve for additional weather sources in V3.