Will females just be able to plop down a nest and lay some eggs or are males required too?
To nest you require a male to be able to imprint an egg to get a baby dragon.
Can wyverns and normal dragons nest together?
No, only the dragons from the same species can nest together.
Can colours mix? i.e red and yellow dragon making orange or red with yellow pattern or vice versa
Yes, colors can mix and to get the most special colors you need to get nested by different color dragons to get that, you can't get it by spawn.
Do you just make a nest and eggs appear in it or is there gestation fun like in BoB?
To be able to lay an egg and to keep it alive, the egg needs to be "heated" the right way with their element to survive. So i guess it is some type of "gestation fun".
Is it only eggs or perhaps live birth?
Atm there are only eggs. I do not think there will be any live birth dragons.
Do I get to play as a swimming dragon?
Right now there are no plans to add aquatic dragons, but we're thinking about it if we get an aquatic terretory. The future will tell us.