Zar Peter already covered the one river 'anomaly' that I saw...

  • #8 - No reason you can't have a lake there, perhaps use the nearby river to feed it.
  • #12 - Some kind of lighthouse or other 'man-made' landmark/building
  • #13 - Could be the home lair of some great beastie of some sort or home to some sea-faring people.


Maybe those'll stimulate some more ideas for you...