I know someone talked about implements like cultivators and discs but what about carts? You could carry more things and carry people obviously.
Maybe we will get carts in the long run
They won't be available in the upcoming mounts update, although there will be special bags which can be attached to the saddle (providing storage space).
Will we have white and black horses?
Most likely yes. At least if the color handling is ready in time... In case we don't make it, additional colors will be available in the update after the next^^
I hope that we get a horse breeding system that will allow us to mix the colors found in the wild
This sounds like a great idea! Unfortunately we still have no ETA for a breeding system yet =/
Has anybody asked if you can shoot a bow or swing your sword from a mount? I think that part would have be intuitively required but I am not sure if they tested it. Would be nice to have mounted archers or nights that fight.
No, unfortunately the mounts will only serve as a "method of transportation" for the time being. However, being able to fight while riding a horse is on our todo list (although this will be restricted to certain items probably, at least bows and firearms), but I can't say much about that yet. If we implement it, it will be a separate update which mainly focuses on these things 
Not to mention can a footman kill the mount? (I guess Pikes need to be put in next.)
Yes, while riding a horse, the player and the mount are still vulnerable. So both can be killed by melee or ranged weapons. In the long run we will most likely add special weapons like pikes and halberds^^
If you look into the npc texture file as of the last update there's deer, lions, baby pigs adorable (spawnnpc minipig), butterflies, rats snakes, spiders and even sharks for in the ocean!
There are indeed some animals which are not in use yet (shark, lion) and some other animals which don't spawn naturally (rats, snakes, spiders). Unfortunately we have no ETA when these animals will be available
Especially spiders (which are supposed to spawn in caves and dungeons) require us to rework the animal AI first.
@red51 if these are coming with the "mount update" please, please, please bring more baby animals to the game. They are so cute
The mini pig is there just for fun
It was requested some time ago. It's not supposed to be the "baby version" of the pig, it's just a "teacup pig": https://en.wikipedia.org/wiki/Miniature_pig
However, real "baby animals" will be added eventually when we start working on breeding^^
Hope we can Armor our mounts.. that would be nice .
Actually we did prepare a full set of armor for the horse, but probably it will be part of the future "combat update" (as mentioned above) 