1. Ya that's correct, you get a lot more point for putting fish in the cannon than harpponing 3-4 times in a chance of getting exp.
2. Ya that's also correct, It will always fetch new tools if you lose any, that's the priority atm, but it should not get caught often by a wave unless it was right in the middle in between the mast or the totem traversring from beach to boat or vica versa
3. There is a chance it can missclick something by accident, that's always the case when botting..., but it will always untether after a few seconds.
All you mentioned is intentional behaviour, if you don't feel statisfied you will be one of the very few.
The script does exactly what it's supposed to do at this point