Sorry I have been sick all weekend and still not great today so very slow with everything from my side... hope I shake this cold soon and can think (and breath though my nose!!!)
If the team moves at half speed you get Advantage on either a Strength (Athletics) DC10 check or a Dexterity (Acrobatics) DC12 check to not be in danger for falling off the side of the mountain.
Yes EN worlds roller is still working. For open ended rolls, etc. I have been using this site Orokos, while coyote roller is down. But you have to register to use them...