The underside of the leaf has an unmistakeable mealy or grainy look. Yes, they're edible (I believe both raw in salads and as a cooked vegetable).

Bookstores here have offered books on Japanese garden plants so there are liable to be ones there as well. If you read Japanese you should be able to use those and other information sources like botanical gardens - where the signs should have Latin names even if the rest is in Japanese. What's different about Trachycarpus wagnerianus is that the fronds look like somebody went around them with a pair of shears and reduced their size by about half or more. Abbreviated fronds with big spaces between them is not necessarily an enhancement. Specimens here look a bit like some sort of hairy fish with fan-like fins.

Now I'm puzzled as to why you asked for an id (using a photo dated 2015) if you already knew its name and had posted about it before? Your plant hasn't got typical Ixora foliage which is why I didn't recognise it. I'm thinking it could be Ixora 'Siam Ribbon' which has curled and distorted foliage. Reading up on its requirements I doubt it will flower in a terrarium as it likes full sun. Siam Ribbon

My best guess would have to be a Bird of Paradise. Most likely a white Bird of Paradise. I had a white one before, and it resembled your plant.