We are doing some renovation on our house over 3 floors.
We need to replace the 2nd and 3rd floor walls since the brickwork was done very badly and the wood studs were built into the middle of the brick, layered in. As the wood shrunk over the years (100 or so) and the house moved, the brick wall became loose. These are standard red bricks.

In addition to that the ground floor wall is built of 8" grey concrete block. That seems solid according to the engineer but it apears to have a length of wood layered in at baseboard height and at ceiling trim height. I believe these are called mule boards or nailer boards to allow trim to be attached in the old days. These seem to be very common in old houses but should they be replaced or are they ok to leave?