I think that you will find that the aircraft in question has 507 engines as on the Avro RJ. Getting to FL350 should not present a problem as you are not carrying 100 pax.
Apart from the occasional smelly air conditionig pack I personally have had no problems with fumes over the last four years.
As to the requirement to fly at 50' that is more a pilot handling problem than. Having flown both the C130 and the 146 the handling qualities of the latter are certainly no worse than the environment that you describe.
As to the prospect of ditching. I spent thousands of hours over the water in the Herc safe in the knowledge that only one ditcing had ever been successful. Even under ideal conditions the aircraft went straight under. Ask to watch the US video.