A Susana y Margarita les gusta mucho el helado.
Why?
Le is for one person, while les is for multiple people.
Me is for theirselves.
Te is for them.
A Miguel le falta el trabajo.
Why?
Les is for multiple people.
Te is for them.
Me is for themselves.
This is how we get both our answers, 1. les, 2. le.
Hope this helps!~