I suspect the kidney stones could've been from all those rich alfalfa pellets. Alfalfa pellets are meant for just baby rabbits not adults. So she's been on rich pellets for years. Probably that took its toll over time. I don't think the romaine would be the culprit but different rabbits have different reactions to particular greens. No harm in cutting out romaine for now. I don't see any problem with other greens however-- particularly if you steer completely away from those known to be high in calcium (like parsley and kale).
Now that she's off the alfalfa pellets and switching to timothy pellets, and she's eating timothy hay (is that correct?), hopefully you'll see improvement. The more grass hay, the better.
Now that she's off the alfalfa pellets and switching to timothy pellets, and she's eating timothy hay (is that correct?), hopefully you'll see improvement. The more grass hay, the better.