Well, from personal experience, I can tell you Underworld Dreams is cute, but it stops there. It's a #$&*@! to build around, and it never quite works out as you expect. Plus, you need M10 duals to consistently cast it on turn 3. Last, I like the little interaction about Jace and Liliana, but I'd go with New Jace. Jace, the Mind Sculptor, has the same interaction, and even better, provided you have fetchlands to flush away uneeded cards after you Brainstorm, and his bounce ability helps your cause further more than drawing them cards, since it accomplishes the same thing (upping their hand count by 1), without giving them card selection. You can also Fateseal to keep the game in check.