The agent is not required to climb into an attic, so it's very likely that the agent had no idea of those problems. Mice can be eradicated by a good pest control company. The foundation can be a very serious problem. This is something that can usually be seen or noticed by the eye of the buyer. On the other hand, I have been in 1000's of older homes where the foundation has settled unevenly but after getting a professional foundation person to inspect, we were told that it has moved as much as it is going to move.
As others have already said, you should have had an inspection contingency with a date as to when this would either be contested or satisfied. If that date has come and gone, then you may not have any recourse. If this is the case, I do not believe that calling an attorney would be a waste of money.
Also, you stated that the "sellers got the home from their deceased parent". Were they living in the home? If not, it is very likely that they had no idea of these problems.
Finally, instead of focusing on misrepresentation, you should be talking to your agent about a remedy. Not sure about the State of Illinois, but in the WI, once a problem becomes known to seller, it is their duty to disclose to other potential buyers. There is a possibility that they would rather work with you on resolving the issues rather than to start anew with a different buyer.