MTI, as opposed to other liscensing agencies, is particularly strict about changes. A production of Songs for a New World, for example, requires Jason Robert Brown's name to be the biggest thing on the playbill, aside from the title, as well as other weird restrictions. But (shh, don't tell) if it's not a high-profile production, no one really cares if you write a book for the revue. They're not gonna check. Just don't parade it around. Or get the rights, and then advertise the show as being based on the original revue. There's usually loopholes, you just have to look for them. And if something's unclear, don't ask if it's okay. If you don't ask, they can't say no.
theatre.