No real ethical issues here Dee. The area you are intereseted in is commonly set this way whereby the Attorny is also the Lisitng Agent/Broker and may also represent the bank or seller.
Now the Agent/Broker/Attorney can handle things in an unethical way if they choose to BUT you can find out by asking them directly what the ethical issues are, if there are any disclosures they need to provide you as an interested party/buyer and this should open up discussion to enlighten you more...
However an individual mls board and/or Franchise/Brokerage may have a different proceedure for making the 'under contract' public information so there is no ethical issue here either - just a choice the listing company or Broker decides to make. They may wish to get a solid mortgage/finance committment for an existing buyer/contract before they want to make this information public. Hope thsi helps!
Listing a property as "under contract" is often postponed until all contingencies have been satisfied. Some multiple listing services have a status called "Contingent Under Contract" that leaves the property on the market. Not all MLSs have adopted the practice of establishing a separate status for these circumstances.