Hello!
Welcome to the forum, I see this is your first post. Your bun is adorable! I would love to see pictures of what the hutch looks like, and as far as building another one, I would just get two x-pens off of amazon. They are usually marketed towards dogs, but are great for bunnies. (Make sure it meets the requirements for height and size.) There are many other forum threads dealing with bonding, and I know the moderators all have great advice! Basically, you can get x-pens and remove the hutch, and then continue with the bonding process from there, you’ll definitely want the new bun to have a week or two to get used to their surroundings though! Good luck! Sorry I couldn’t say much more.

How big is the current hutch? It sounds big? I routinely have done what you describe, where I basically tuned one giant condo into two smaller ones while bonding, but both were still of acceptable size. Then once they are bonded you can just reconfigure back to the giant size. She might be grumpy at first but she will be fine. 🙂 Expect some thumps!

For exercise you can do alternating times, or same times as long as the rooms are safely divided up. It helps with pre-bonding if they can be out at the same time and able to see each other. I have often used a doubled up x-pen to divide the main room so there is a buffer of about 6 inches between the walls so they can’t nip each other through the fence.  Just be sure they can’t actually get at each other. You’d be surprised how determined bunnies can be to get at each other before they are bonded!