
Is that Dr Jeager??

I don't think so, it was already established that Grisha (Dr Jaeger) died. Maybe he had a sibling or an identical twin though that seems implausible. Perhaps the fact that Grisha's titan and beast titan seem to some similarities maybe he's an ancestor? Like Ymir? He seems old enough. Plus he didn't know about the 3dmg.

Eren's dad had dark straight hair and this guy has light wavy hair. In manga that makes all the difference XD Seriously though, it's not Eren's dad. Grisha is dead for sure or else Eren wouldn't have the king's memories. Not sure who monkeyman is, but I hope we find out soon.

I remember there were Annie's flashbacks of her father in both the manga and the anime (during her second fight with Eren). I think the man doesn't look like the ape man.
(≧∀≦)