I found the issue with the forecast. It’s a binding bug. If there is no item linked to the weather channel, the binding won’t ask the Ecobee server for forecast info. Can be worked around by adding a dummy item like this:
DateTime VT_Outdoor_WeatherTimestamp "Timestamp [%1$tA, %1$tm/%1$td/%1$tY %1$tl:%1$tM %1$tp]" <time> (gWeather) { channel="ecobee:thermostat:account:411921197263:weather#timestamp" }
See this post: Ecobee binding v2 - #38 by jakdock.
Still scratching my head on the Celsius display problem.