If they overdose all that will happen is that it would have a laxative effect. ;)
Don't worry about it. Just about anything is toxic in overdose but when it comes to natural, unrefined oils of an already nontoxic nature, all that happens is that they get the runs.
This is a good thing in...
Yes, it's good for them, though the flesh itself can be hard for them to consume whole. The coconut oil is anti-giardia, one of the few things you can use to treat that, and just generally all-round good for them. I used to feed mine Copra (coconut flesh after being pressed for oil, a protein...