It's rumored that the release date will be October 28th. If that's true then I see this:
March: Starters, some new mons (most likely the mascots), region name, maybe a map
April: Regional Rodent, and bird if they're not amongst those included in March.
May: Some random new Pokemon and map if it's not shown earlier. Some Megas
June: New Volcanion forme, or more details on Magearna. A mega or two
July: Even more details on Volcanion and Magearna. Perhaps a mention of Volcanion possibly unlocking Magearna's event. Starter's 2nd evolutions
August: Evil team. Megas of the leaders
September: starters 3rd evolutions
October: Last Corocoro, summary. Maybe a few last minute megas, or a number of how many Pokemon they might be, like _+ instead of the actual number.