First of all, thank you for thinking about doing something. I am a long time advocate of taking action before its too late and have been constantly ignored so I feel like I have got a bit of support now.
I'll reply to your points sequentially
Corona will be there for at least 6 - 8 months (could be more) and there are people who are in desperate need of help in the current situation. Because being on bridging visa or 489 will not get you any financial assistance from the Government. We can pressurise the department to allocate more COs to 887 visa because due to travel restrictions/uncertainty in the world, no other visa holders will come to Australia anyway.
None of the 887 holders will come forward. They've moved on with their lives and being an immigrant they will not take on the department for us. Also, since the complainant has got what he was after, the case will be so much weak that the department wouldn't take it seriously. I suggest we should do it as a group to take collective risk or someone from the current applicant should come forward.
There are many 489 visa holders that live in other regional areas and in more desperate circumstances and they want to contribute too. Arrange an online meeting and get everyone involved. People will be happy to contribute.
We can launch both complaints as a group
You must follow up the cases otherwise you will not get media/politician attention. Also, this will be the service to all those who are on 489 and yet have to apply for 887.
We can't hide behind another 887 holders. If we want to do something, we should be brave enough to come forward.
Yes, there are many difficulties people would love to share. Especially the folks from real regional areas.
This should be a collective cause, everyone should come forward and contribute.
Once again, thank you very much for thinking about taking some action.