I was worried because they look all black and wasn't sure if it was a problemThose cement resistors do get hot, you can replace and leave the legs longer to get more airflow, I don’t know if it’s down to age of component or just design.
I'd remote them well clear of the board too. No matter what you've replaced them with for the cost and time of taking the batteries away from the boards is good move.Change those batteries while you're in there. Alkalines are time bombs. I'd recommend Energizer Lithiums off Amazon (not ebay..!)