You get up in the middle of the night because that's when your REM periods are up and going (a significant majority of people find it extremely hard to WILD while going to sleep although it is possible and some find it easier to do before sleeping than after 6 hrs)

The reason you've been getting into SP but no further is probably because your mind isn't going into REM (the necessary state for dreaming) the reason its not doing this is because normally it has to go through a few other stages before that (which takes awhile) and since your being conscious isn't actually affecting anything, (your just along for the ride) you would have to sit there for awhile to get into REM

HI is many things for many people, it can be vivid imagery or dots (or can start as dots and turn into imagery) or if you like me you might not get HI at all (until like 30 seconds before your in the dream, then you see it forming around you sometimes)

hope that solved all your problems