3yr old & 5mo old coughing runny nose, slight fevers, phelgm n chests, 5mo old a little hoarse. both still eat and play. diagnosis/suggestions please?

Viral most likely: Sounds more like a viral upper respiratory infection shared between the two of them. Good they are playful and eating well. Keep them hydrated, keep close eye on fever especially for the 5 month old, high fever, irritability or compromised feeding warrants visit to pediatrician. Older one worsening of cough, ear pain, high fever same suggestion.