Hera smiled as she held Kazuda Xiono in her lap. She had never expected to have a grandkid. I mean, she didn't even expect to have a kid!
Before Kanan died, when she first found out she was pregnant, she didn't expect it too survive. Human and twilek kids usually had problems that killed them young. They also were usually infertile. So grandbabies were out of the question for Hera.
But once Kanan died, she knew Jacen would live. She raised him and lived for him. She even sat out the Battle of Yavin for him. (going to battle while giving birth was difficult, to say the least.) When all the rebels went to Hoth, Mon Mothma forced her to stay on Lothal, simply so Jacen would have his mother with him for a little bit longer.
And once the war was over, she raised him on the Ghost, flying free around the galaxy. They visited Lothal, and 'Aunt' Sabine, who taught him how to embrace his green hair. Lira San, with Uncle Kallus and Uncle Zeb. (Hera was still grateful for Zeb acting as 'Father' for the first few weeks, proudly showing off Jacen just as Kanan would have if he lived.) Ryloth was visited less often, and only once her Father had finally gotten over the fact Jacen was half-human.
Jacen was smart, picking up both Ryl, Basic, Binary, and some Mando'a, Lasat, and Lothalian, (in honor of Ezra.) He was a skilled pilot, a talented mechanic, and would make a great husband (Sabine teased him during the teen years.)
Eventually, a nice human girl came along, and Hera's baby was off getting married. Hera spent half of her savings to buy them a beautiful ship as a wedding gift. Jacen took her last name, not because he didn't like the name Syndulla, he had assured Hera, but because he didn't want to always be compared to Hera. Hera didn't mind though. Jacen Xiono was a great name for anyone.
And now, they had a son, Kazuda Xiono. Born with the New Republic, able to enjoy a peaceful childhood. (Hopefully. This First Order was making Hera nervous. But at least they had Luke and his new Jedi Order coming along. She was sure they could handle it.) Hera was glad to be able to be a part of it.
"And you know Kazuda." Hera cooed to the month-old baby. "It's not my fault if the Spirit attaches perfectly to the Ghost, is it?"
Kazuda kept on sleeping like a baby.
So, I noticed in that Image of Resistance running around that who I assume was Kazuda looked like Jacen and Kanan. So, my theory is Kazuda is Jacen's son.