A review hearing is synonymous with a status conference. The court wants an update on what is happening with the case and if it is going forward. A default hearing is where they hear the default while the request is simply request to default the other party.
This is just my opinion and not a comprehensive answer. You assume the risk because this answer may not apply to your situation depending on the facts.
First, you or your representative should be present at all hearings. Second an example of default is where you serve divorce papers on someone and they don't bother to file a response with the court. Sometimes, you can even have a person's pleadings stricken by the court and then proceed with default.