Are Awakened Zoan users able to change form? We have been introduced to 5 characters (all Impel Down Jailers) with "Awakened" Zoan Devil Fruits. Minotaurus is the most famous of them. A normal Zoan fruit allows the user to transform between Natural (normally human), Animal (based on the devil fruit type), and Hybrid forms.  I can't, however, remember any of the "Mino" guards in any form besides a exageratedly strong version of the Hybrid one.

At the time I thought "Awakened" meant that the fruit was always active so they were stuck as partially animals (as well as give the strengths Crocodile mentioned).  With Doflamingo's Paramecia fruit, however, awakening appears to just unlock new abilities.  This made me doubt my previous understanding.  Wiki doesn't help and I don't have time to rewatch everything.

Do we know whether Awakened Zoan Devil Fruit users retain the ability to transform into multiple forms?

If the answer to this is "Oda hasn't told us yet", that is sufficient.
I don't believe Oda has told us yet, and with how nebulous the definition of what makes for an "awakened" devil fruit user is, without canon stating one way or another there's not really any way we can solidly theorize a yes or no. I would presume that they would retain their ability to transform back and forth because that would make Chopper kind of lame if it didn't (but he'd be a pretty good golfer, because he'd lose all of his points [insert rimshot]), but again, without canon describing it we can't say definitively one way or another.