What are you seeing that "looks fried"? I don't see a problem on the solder side of the board that you've posted an image of, so I'm guessing whatever problem you see must be on the other side you haven't shown us.
What specific components do you see that are fried on the parts of the controller you haven't shown us?
What specific problems is the system having, under what specific conditions?
What troubleshooting has already been performed? (please list step by step, along with the specific results of each step)
What was the "accident", and did the system still work after that? Or what specifically happened and was damaged, etc., if it didn't work? Those could be directly related to why it doesn't work now. Not knowing any of that we can't say what might be wrong.
If it did work after that but only stopped working after the throttle replacement, then it would help to know exactly what was done during the replacement process, what it orignally had and exactly what it was replaced with, and exactly how the original was wired and exactly how the new one was wired in place of it. Not knowing any of that, we can't know if anything else was damaged by a miswire, incompatibility, etc.
If by "need a display or not" refers to a new controller, you would have to check the requirements of whatever new controller you choose. If you choose one that requires or uses a display, be sure to get the display with the new controller as a kit, to be sure they're compatible.
For us to help find a compatible controller for the rear motor, we'd need to know what that motor is, what it's used for, and what features you want or need the system to have.
Or we would need to know exactly what the old controller was, to find an exact or compatible replacement.
More info is more helpful to help us help you.
