I just checked Sagemaster15's YouTube channel and there is going to be two new characters coming to Heroes. And plus, he saids those two Cipher cards were labeled under in Heroes, but I haven't checked the official Twitter post yet, I only just saw the video. The first character is a princess named Alice (with a Staff and a Tome) and the other character is a Knight who appeared to be a butler like Jakob.
Edit: I just checked the official Fire Emblem Heroes Twitter account, it doesn't look like those two were shown. It's definitely leaked.
2nd Edit: Sorry, disregard with the topic, I just found out those two characters were original characters for Cipher and they were been announced in Series 10 already.