java fern is by far the easiest in the list. Mainly due to its ability to grow in less than great conditions (low light, low nutrients, no CO2
), but just as importantly because it is a slow grower. This makes for diagnosing deficiencies more difficult than fast growers, but its less susceptible to those short-term deficiencies.
Hygro is a very easy plant to keep BUT they are resource hogs and grow very quickly (cause deficiency in tanks not properly maintained). I would take java ferns any day of the week over hygro or others you have listed, and they can look very nice as a species-only tank. I've often thought of making my 10gallon tank a java-fern only. Very low maintainence and nice looking. Also the tough leaves are not eaten/damaged by fish often.