My husband and I both use the 800K for ours. I believe it saves us money as the structure of it allows us to use some of the funds (You need it in there for the 3 months before and 3 month after application / 4 months before the end of your Visa I believe - could be wrong for your situation so check) at any rate it allows me 5 months to use half and transfer monies only when the AUD is up and allows that money to build interest in our home country while we wait - plus we are only paying the 1,900 each immigration charges when applying so that works well for us but you need to look at your own situation and see what will work best for you.
Once you get your new passport you will need to take it to immigration to transfer your visa into it. You keep the old passport the form just needs the number so take the old and new passport to immigration
it is per person. I highly recommend doing this rather than trailing spouse simply because if the main spouse has to leave or god forbid something happens - trailing spouses only have a short period to leave.
Once the bankruptcy has been discharged it's no longer relevant. If you are still in process of the bankruptcy, you likely cannot leave the country until it has been discharged. I am assuming you have it discharged though and are financially stable now.
We weren't even asked a question about it during our application, so it never came up. Had it I would have had to say something as I filed it years ago after a divorce that left me financially struggling after he emptied my accounts. (yeah, sometimes it is the woman who gets screwed over, believe it or not) they never asked and it never came up through the process.
You will need to fulfill the financial requirements to gain the correct visa. For example ours is a non O retirement - 800,000 Baht retained in a thai bank and I think there are times you can use a portion (but better to just leave it there for insurance / emergency use purposes) and then you need enough to live on besides those funds.