U can find the mushrooms very easy on the same place u find the blood wyverns. U can pick with your hand in the little mushrooms on the grass. U can find the featherlight on the northest but it have a little life and the region is very dangerous, so pay attention, probably It will die by something (like a rex, carno...). Will be good if u lock the featherlight in rock structures, then any dinos (that spawn there) can kill it while u tame.

More Featherlight Taming & KO Tips