If you are only moving PAX you should look to AS350 D or BA+. Both are Lycoming engine.
AS350 D = 4300lbs max gross If my memorie is good.
AS350 BA+ = 4960 LBS max gross
Almost the same engine just an upgrade one same power but with most of the new SB on for the BA+.
You have around 2000lbs of payload with the AS350 BA+ and the DOC is almost the same as the AS350D. Lot's of D model converted to BA+.
As a AME I prefer the Lycoming over the Arriel because you can do almost all the maintenance on it. I heard that it's cheaper to operate, around 50 $ less an hour.
With a Lycoming if you don't pull to much power you can get 3,5 to 4 hours of flight with 1 full tank. The arriel engine are not good at low power setting for fuel economy because of the bleedvalve. So if you run a low power this bleed valve is always open and you burn lot's of fuel for nothing.
For the corrosion here in Canada we don't have that problem. So not able to help you for that.