Definately go Greater. 2nd level has too many spells you are wanting, but there are fewer absolutely critical 4th level spells. Stoneskin is a trap, it costs too much to be worth adding as a Spell Known. Black Tentacles and Solid Fog are both very good, but you may want to choose one or the other, since they both do similar things. Dimension Door is handy, but Teleport is just next level, and you don't need them both. Confusion is a Save or Loose spell, but it is mind-affecting. Seriously, it might be right up your alley, though. Re-read it. Phantasmal Killer has TWO saves, AND is Mind-Affecting, so it has too many ways to NOT work. Enervation, however, is a MUST have.
So you have Black Tentacles/Solid Fog, Enervation, and... confusion. You've still got another slot you can afford to throw Greater Invisibility into, and that way you don't get revealed when you start screwing people over. You can charm a whole encounter by yourself before having to reveal yourself.