What is the best fever and cough nedicine for a toddler?

No cough meds. There are NO GOOD cough medicines for toddlers. The studies very clearly show they don't work and have undesirable side effects. Try some honey in tea, warm showers and a humidifier. With regard to fever reducer, remember fever is just a symptom and doesn't usually "need" treatment. However, if the child is feeling bad because of the fever, then acetaminophen and ibuprofen work equally as well.
For fever. fluids,Tylenol (acetaminophen) or ibuprofen. No OTC cough medications for children they do not work ad can be dangerous if given too much. A cool mist vaporizer is helpful.