The Franciscans are a religious order (usually Catholic) and they form a brotherhood. They follow the teachings of St. Francis of Assisi
The embrace things like: proverty, meditation, prayer, and serious study. Moreover, they are Christians.
When it comes to agnositc, we are not dealing with a monolithic group at all. The only thing that they have in common is that they do not know whether God exists or not. Apart from this, they can be different as day and night.
When we compare Franciscans and agnostic, the greatest difference is belief in God.