Are you trying to get more lift to level out your front end, or simply to add more lift? If you're trying to level out, look into coil spacers or new front coils. Also, simply installing a body lift won't necessarily give you more flex- if you're already hitting your bumpstops/maxing out uptravel and you aren't rubbing, a body lift won't help in that regard (at least to my knowledge- feel free to critique me, guys). Now, if you DO rub, or want to tuck your gas tank up a bit, a BL can be helpful.
As for the tummy tuck, no, they aren't required. JeepForum has a pretty in-depth article on doing one ( So you want a Tummy Tuck... - JeepForum.com
) that lists various parts you will need. You might have some of the parts already since you're running a lift, too. Average ballpark cost is around 1200-1500 if you don't already have some of the parts.