Question
I was told by a friend that Ficus smells like pee when used as firewood. Is this true?

Answer
After the wood dries I would see no problem using it in the fireplace. In fact there is very few trees that could not be used for firewood. Once you get a good bed of hot coals going the ficus wood should do fine. It of course will not burn as well (hot) as say seasoned oak.
Most trees that are not dried for firewood when burned give off odors. Ficus is used worldwide for firewood with no problems.