I choose none of the above. Variety is nice. "Caldanese" is a term with some history to it. "Napanii" is something a bit different. I like the name "Amarrad". "Amarric" sounds neat, but both are a bit contrived. In general, something other than just [empire name]+[suffix] is cool. I'd prefer "Garounais" to "Gallentean" any day. And remember, the names of individual languages can be as varied as the number of foreign languages that have names for them.
The official dialect of the Chinese language, for example, can be correctly referred to in English as "Chinese" or "Mandarin". If you're talking about the Chinese dialect of southern China, the name "Cantonese" is just as correct. There are smaller dialects as well. "Shanghaiese" (known as 沪语 Hùyǔ), for example, is also 100% "Chinese". Same for the dialect we might as well call "Taiwanese". In its own words the Chinese language can go by more than one correct name, such as 中文 Zhōngwén or 汉语 Hànyǔ. Languages and dialect families are often too large to be aptly summed up with single names. And this is just on modern Earth. In New Eden, it's a big cluster, so... more variety!