Broadly speaking, do you have a current interest in the issue, or do you have sufficient standing to bring a claim for the benefit of those that do?
IMHO, #3 is the only one that has any semblance of legs, with #4 and #5 perhaps adding a degree of credibility.
N.B. Nobody outside of the Administrative Court is qualified to answer your question.
The only example I am aware of from personal experience is the Consumers' Association appearing as an interested party in the Supreme Court in Beavis.