defending little blind when structure is 2 chip, 3 chip.

[Romulet]

Same range to defend vs a raise, 3 bet and force the bb out as you would in the normal structure. To 3 bet or fold you need a fairly big hand to play in the first place, the good news is when you do win you'll win slightly more money. The difference in this structure is that you defend with virtually any 2 cards against limpers and of course, as you state above, you can defend the bb slightly more liberally.