#1
Uper image 10 cm tower pile of dirt, having hole thrue it, hole going into ground.
Slovenia, like 10 m above sea level.
#3
Newer seen that, lots of those around there, I think there is no way I could find that in NW Slovenia where I live, I think it is south, sea level dependent.
#4
this size, you should consider a member of Megascolecidae, although fauna europea says there is no species of that family in Slovenia. If you ever come across this large earthworm member collect it in (96%) ethanol and send it to specialist.