Ahaha, I had a feeling that would be the case. Bulbapedia and Serebii will hopefully have all you need for that ^^;;
Feel free to play Heatran as grumpy! I don't mind at all ahah.

I had a feeling you would like to play Ho-Oh, it also gives me an excuse to play Lugia as a Flirty fucker towards the rainbow bird ahah.
You can take the Forces of Nature and the Swords of justice if you'd like! I'd just like to be able to play Keldeo, especially as Keldeo and Kyurem have a bit of tension between each other ahah.

I can do the horses while you play Calyrex, that's absolutely fine! And yeah, I feel like Bear will either love or hate Zarude xD I made Grookey it's guardian too so there'll be three monkeys to deal with ahaha.
As for the characteristics I can't think of anything right now, if I need to bring anything up I will, but play them how you think is right, I don't mind at all!