Advocacy is not allowed. If you want to quash a judicial meeting just inform the elders that you will be bringing your attorney.
The answers to your other questions depend on the elders involved and, at times, the degree of the service department's involvement.
Every appeal committee on which I served reversed the original decision and the service department honored our finding. In one instance though, and this involved a special committee attempting to resolve a business dispute, it became clear that the service department had already passed judgment. When our committee came to a different conclusion, we were fired and replaced with another special committee who, while agreeing with our findings, were off the hook when one of the parties confessed to sexual immorality. The new committee took disfellowshipping action and in this way, the matter was resolved.
I have seen compassion, reasonableness, mercy and wisdom at times; but at other times, politics, ego, faovitism, Simony and dishonesty.