That is a mockup. Be prepared for some of those listed features to not actually be there. As always, anything "Leaked" that has to do with an Apple product needs to be taken with a grain of salt. No one has ever predicted an Apple product perfectly in advance of its release. Someone will most likely come out the night before with a perfect prediction, but in the world of Apple gossip, the night before is too late.
If it has OTA data capabilities, then being able to place calls with the device via bluetooth headset would be an awesome feature. One less thing to carry around if you need your tablet with you. As you know, Apple spends lots of R&D time and dollars on convergence, so it wouldn't be a surprise.