Well yes potentially you should be cautious because rabbits need to be introduced to new foods slowly, inc leaves etc. Also there are many plants that are actually toxic to rabbits.

Considering you got them probably around 6 weeks old? (which is too young really to be leaving their mothers) they should really still be on pellets and hay only right now, so as long as you’re feeding them that they aren’t missing anything in their diet. Most bunnies are quite piggish. At 12 weeks you can start slowly introducing leafy greens one at a time, and at 6 months you can slowly introduce fruits and sugar veg like carrots and peppers.

I know you didn’t ask this, but I also just want you to be aware that at this time you really should keep your bunnies completely separate from each other at all times. Any time after the 2 month mark bunnies can start becoming hormonal. Hormonal bunnies will only want to fight or mate, and they can seriously hurt each other (think chunks of ears gone, testicles bitten, noses bitten half off). They should both be spayed/neutered before going through the proper bonding process. I know they may seem all cute and loving now, but it really can change in the blink of an eye and they can become violent so quickly, and if you’re not there to intervene it can be deadly.