In theory and on the day of certification of a power plant you will have 100% containment of the engine nacelle. Meaning nothing will penetrate. However as the entire engine ages, penetration is possible.
As to vibration after having thrown a fan blade, or anything else for that matter, would generate an engine vib above 2.0 on the indicator, requiring an engine shut down.
Most 777 are operated with the GE90, on which the first stage compressor blades are full composite.
