Eddie, you are a smart guy and I'll only make a few comments for your awareness, likely you have already thought of these.,
If Karen hasn't trained horses successfully, when the time comes, they will need to be taken to a professional trainer.
A trailer for exotics is quite different from a cattle trailer. Look at what the people use to take stuff to exotic auctions. I think that higher, wider, more enclosed, darker, will be the general direction. I only know a little about exotics, but understand stress can be a VERY significant killer.
You said "exotic pets"... I think of pets as critters that will eat out of your hand and let you brush their coats and follow you around and are not dangerous. I have GENTLE cattle, but not pets. When the boys were in 4H, their cattle were pets, could lead around, etc...became dangerous when grown because they had lost their respect for people and would treat people as a member of their herd. Thus, they would push on people, not get out of the way, etc.....
The pens you have to build for exotics will work for cattle. Might be a good idea to visit an exotic ranch and watch them work their animals, see their setup and how it operates, how they load into a trailer.
I would have concern for the exotics you mention because they would have horns and could inflict injury if close to a person and swung their head to swat flies....not malicious, just being a critter. Then, there is the rut season....I know people who raise white tails...must cut their horns off to avoid killing each other during rut fights. Also, study on what each animal grazes on....your 30 acres will hold only so many grazing animals. And, it's not hard to find cases where wild animals which become accustomed to people will try to mate with them, or attack them to get food...etc...you get the point. I do not "pet" any of my cattle, when they come close, I make sure they stay a respectful distance so I don't get hurt...both in the pasture and in the pen.
As regards cattle, it makes sense to me for you to have an arrangement with your brother for the occasional animal you wish to butcher.
You may wish to start a separate thread on exotic raising...haven't seen one on TBN, should be interesting.