I hope the panda will make an appearance too. It makes sense after all because we never got to see the panda in action, but with a side series, the author can do whatever he wants with those non-revealed side scenes. Just like he never revealed how Reika made it out of that situation, and so, he can make something up.
Still though, I don't like the time traveling idea.. doesn't make much sense to me.
About Sutezo, and the child he revived. She doesn't know about him being partly alien, so Sutezo "coming out" is certainly going to freak her out.. I'm not sure a child would want to stay with someone like that, so it feels like their relationship is bound to fail? She's scared all the time already as it is...