Looking at this concept in further detail, it appears BMW have have simply taken a fuel cell concept and rebranded it as a BEV. The clues: 1. Big *** grill, fuel cell needs a fair bit of cooling. 2. Blue accent lighting on the rear bumper where tailpipes would go. Blue to signify water expulsion. 3. Big engine bay, look at the amount of space from front of dash to front bumper. 4. Non fold down rear seats to accommodate hydrogen tank bump. https://insideevs.com/bmw-inext-concept-revealed/
I was at the event and wrote the above mentioned post. In short, no, it was never designed/developed for hydrogen. This vehicle was born to be the "BMW i version 2.0", as said by Klaus Fröhlich, board member for development. It's the basis for the second generation of all-electric vehicels coming from BMW i, there's no H2 talk or plans for iNEXT at all.