Tech specs indicate it remains a Lightning port on the 9.7 and 12.9 inch iPad Pros.

Odd differences in the iPad Pro lineup:

• 9.7 inch is USB 2 with the 12.9 inch model remaining the only USB 3 iOS device
• 9.7 inch has a better screen due to the true tone color matching
• 9.7 inch cellular model has an "Embedded Apple SIM"
• 9.7 inch model has 2GB of RAM, whereas the 12.9 has 4GB

I did see a random rumor float by that the iPad Pro would charge via USB C using the Lightning to USB Camera adaptor. I've yet to see a confirmation of this though.

Personally sticking with my iPad Air 2 for now. It's approaching 2 years old and still remains a fantastic device. It's my belief the "slowdown" in iPad sales is due to their long lifespans. I'll probably seek to replace the Air 2 with whatever 9.7 inch Pro model is out in late 2018.