I wouldn't bother with the TTB, that swap would be way more hassle than it's worth.
What are you looking to do with your Libby? What kind of trails do you want to run? What size tire do you want to run? Depending on how you respond to those questions will depend on what you ought to do. You might be better off modifying the IFS to work for your needs.
If you're going to do a SAS, you might be best off using something like a Early Bronco Dana 44. They're about 56" wide, which is probably a tad wider than the stock Liberty width, but I don't know off hand. Also, do you happen to know what side the transfer case drop is on? If it's not driver drop, then a Ford axle might not work for you.
Or you might want to consider a TJ front axle, again depending on the t-case drop. That would be a sweet setup, use all Jeep parts. And if you're going to do all this, there's no logical reason to try keep the rack & pinion steering.