Dead-end or no jobs (The Witcher 3: Wild Hunt)

1. In the area between the village of glinnik hut and boat masters have 4 at home in one of them a dead woman and a furnace, both highlighted in red. Geralt examines but says nothing and nothing happens. In another house a dead man, and next on the window tracks like children's feet. I think that should be the job. Tell me
2. Near est Tayyar, in the North - East are the ruins of corpses, and on the top near the sockets there is a chest closed. Can't find the key itself.
3. Why red knights? Win difficult, but awards no?