I've lost track of what has been going-on with research rewards on my main account.
My new account has had Suicune and Zapdos so far.
Hope we get something new soon.
2 and a bit weeks (end of Feb) for the rewards to switch which will also be when the T5 boss changes over however what do they switch to ?
The Pokemon go website and twitter pages have all had 'paint splashes' added to them which is making people think Smeagle however that could be a quest reward rather than your research breakthrough
If they kept going in order the next thing would be Kyogre / Groudon / Rayquazza but i'd expect Ray to be back as a raid boss first (with the chance of a shiny) - they could bore everyone silly and give out the Regis ?