They didn't specify how many DLCs, and the PZ console port was it's own category in that presentation, not even confirmed as Planet Zoo then. June is the more typical time after Easter, but is not this financial year.
The current Frontier publisher sale does look like attempting to increase the customers for the nearish future, which might be what they'd want to do if they had more expensive finale DLCs lined up for both games. There's also the next F1 game in midyear, but that's pretty much all there seems to be in the next few months.