Finally, from 10th April 2017, three types of JR-Pass will be valid to use in Kyoto Tango Railway(KTR).
*Kansai WIDE Area Pass
*Kansai-Hiroshima Area Pass
*Kansai-Hokuriku Area Pass
For further information, you can read on their official website.
https://www.westjr.co.jp/global/en/pdf/press_20170215.pdf
Travel inside of Tango region, theses passes are not that worth it, so if you are staying over night in Tango region and try to utilize these passes, I recommend you to travel into Tango region on the last day of the pass or travel out from Tango region on the beginning of the day of the pass.