I am breaking down your question into smaller pieces which may help clarify........
1. You mentioned "redemption period" and usually that is specific to foreclosure, not necessarily bankruptcy. A "redemption period" is a legal time period in which the owner has to "redeem" their property after a sheriff sale either by obtaining funds to pay off their total debt, sell the property to pay off the entire debt, or negotiate a short sale to satisfy the debt. In Michigan, there are two options when it comes to redemption periods. If the property/home is on 3 or more acres, the redemption period is 1 year from the date of the sheriff sale. If the property/home is on less than 3 acres (2.99 or less) , the redemption period is 6 months from the date of the sheriff sale. Agents can find these dates on public records for you.
2. If there is a "bankruptcy" in addition to a "redemption period", you've got double the headache! Not only will you have to deal with the bank or asset management company to negotiate a sale as it relates to the foreclosure, you will have to work with bankruptcy attorneys and/or receivers or trustees of the bankruptcy. Anything to do with the subject property has to be approved ifirst by the lender and then in the courts. Good luck if that's the case - you will need it!
3. It varies bank to bank as to whether or not they will accept an offer during the last days of the redemption period. In my experience, I've had banks that wouldn't work with me if the deal couldn't fund on or before the redemption period ended and I've had banks who have taken offers in the last days of the redemption period, especially if the buyer is a solid buyer. Trust me, banks don't want any more houses!
4. In most cases, buyers agents won't have any information other than what can be obtained by public records. If the selling agent doesn't give the details, how is the buyer's agent supposed to know otherwise?
5. When dealing with foreclosures, short sales, homes which are included in a bankruptcy, etc., it becomes VERY important that you are working with an agent who has experience in these areas. There are a lot of agents out there that have zero experience in these areas. I wrote an offer a couple of weeks ago on a listing in which the listing agent had typed "subject to short sale" in the comments. When negotiating the offer, the agent said she had actually never worked on a short sale, but that she had heard of them before! Can you believe that? It's a reality!
6. Ethics are the professional standards by which Realtors work. Agents have an obligation to protect, educate, negotiate, etc. If your agent didn't have the information, I don't see how this would really be an "Ethics" issue. As Realtors, we are wading our way through all of this too!
Best of luck!