Should I still qualify for an MEB for chronic compartment syndrome, despite refusing surgery due to its 50/50 success rate?

If the subject matter expert, the person responsible for referring you to a medical evaluation board, tells you that you are not qualified for it, then you are not qualified for it. Any recommendations you get here that run counter to that information are going to be conjecture, and worth about as much as the information you'll get from a Barracks lawyer.
As for the reclass, doctors add health care providers usually give inaccurate information about medical reclass. The only thing they are authorized to do is to state limitations of your condition. If those limitations still allow you to be employable then you are referred to a medical reclass.
When you received your medical reclass, you will receive a training date and follow on assignment instructions. They will require that you add time to your contract. If you choose not to add time to your contract in order to meet the commitment that you need for PCS, then your training will be canceled and you will ETS

I suggest you sit tight and finish out your time. Don't do anything that would screw up your DD 214

Listen, get with the local IG and ask them the question. This is not a case of someone lying to, or withholding benefits from you. If they are wrong it is a mistake. You deserve to know the facts. Having said that, should the military be held financially responsible for someone who is refusing treatment. What are the downsides with the surgery and without. Become informed and make a more appropriate decision for yourself. Thank you for your service.