1/ yes, difficulty bug is fixed
2/ if you are playing without mods, you should finish the game somewhere between June 1999 and December 1999... anything else is "prolonging the pain"
3/ if you shoot down UFOs regularly and don't have 4+ mind shields in each base, you should be seeing quite a lot of alien retaliation (base attacks) by now... if you are not try posting a saved game and your config file so that we can have a look...