This is awesome. I really like Rockruff's evolution formes, although I prefer the day version, I still really hope that we can catch Ultra Beasts. If we can't I understand (since its heavily hinted at that UB-01 is Lillie) but I would still very much like for them to be catchable. As for UB-02 Expansion, type up Soul Eater Mosquito 100 years.
Judging from the fact we see Expansion battling Tapu Koko and that there's a Island Guardian for each of the four islands, it might be plausible that each Island Guardian has a opposite, which are the Ultra Beasts (with the exception of UB-01, who seems to be on either side), that would mean there are 5 Ultra Beasts per game (9 Ultra Beast if each UB is different between the games like UB-02 Beauty and Expansion).
Judging from this leak, we'll just see an official reveal on Wednesday, maybe a couple extras.
One thing missing from here, that may be added later on, is that the leak reveals that it will show the true strength of the new Pokemon, Type: Null, during its next issue.