The SB2 form would be needed to have the new shares start trading. The EXBX shares would continue to trade unless they were actively canceled by the company.
I don't know why the company wouldn't disclose this. Perhaps they just knew in their heads everything that was going to happen but didn't do a great job explaining it all in their public releases.
I agree that it would have helped tremendously if the disclosures were a little bit more clear on everything.
I agree that it seems too good to be true and if it is too good to be true then it usually means that we are missing something. I think it would have been a simple matter of another press release to clarify the intent. Not sure why the company didn't do this.