Okay wait! Before you get Bandit a friend, is he neutered already? Because if not, you might have a hard time bonding him with his new friend. If he is, I'd suggest to make him pick his friend and maybe arrange a playdate in your local bunny shelter. They can also tell you if the bunny is litter train and/or fixed already
With regards to the set up, once both bunnies are fixed, you'll have to bond them first, this might take some time so it would be best to have separate enclosures and supplies first. Once you're sure they're fully bonded (no fighting for 48hrs straight), then you can combine their spaces.
- A bigger litterbox is needed for two or more bunnies. I have 3 bunnies who share one litterbox which is an old "large" rabbit cage
- if possible, use a waterbowl as its more natural for them and they can drink more compared to a bottle
- food dish hmm I personally dont use a food dish as I use enrichment toys and to encourage foraging. you can make them share a bowl but it might be hard for them
- enclosure would depend on your living condition, if you can get a pen that would fit the minimum size requirement for two bunnies (minimum requirement for 1bun is 6ft x 2ft x 3ft), that would be good! If you can afford to free roam them and get the place bunny proofed, thats great!