Well I haven't been able to find anything toxic in the Hedychium genus, but you should always take great care to find out if your plant is the rare exception! I found a site that saysH. coronarium has "snow white insides of the edible, spicy tubers (not the ginger of commerce, which is Zingiber officinale)." http://www.ces.ncsu.edu/depts/hort/c...ls/Hedycco.htm
and as this is a university (NC State) site I think this information can be trusted. You could try to look up any other plant you are interested in there as well.