Deliverance,
Each engine type has different tolerances depending on the design of the blades on the inside. FOD is still the No 1 ECU killer across all types although some are more prone than others - Harrier is a hoover, and the F16 has issues as it's intake is so close to the ground. From an engioneering perspective its down to how quickly the engine can be replaced to make the jet flyable again. The Harrier is awkward as you have to take the entire wing off whereas I beleive an F16 can have an engine replaced in about an hour(it just slides out and back in). Tornados have issues with water collecting in the intakes and then 'soft' fodding the engines. Its unusual that one intake be dried out but not the other, hence leading to a double rejection.
Once in the air birdstrike is probably your biggest issue, such as the Tornado that went down over the Wash last year. In a single ECU jet one big bird will do it (Indian Harrier 2 seater went down to a barn owl last year) at least a 2 ECU jet has a chance, but birds tend to flock and sometimes it just isn't your day.