Good news for you,duty is same for new gen fit hybrid as current one as both fall under 1500 cc categeory.and new Fit shares engine with Honda vezel.so engine parts wont be a problem as already Vezel is being imported increasingly now.
Some interesting facts about Honda hybrids being imported are below.i divide them into three pairs
1: Honda insight and honda fit gp1(1340cc) both share same engine
2: Honda Fit RS(1500cc Gp4) and CRZ both share same engine
3: Honda Vezel and 2013+ new model of Honda fit hybrid shame same earth dreams engine.
All the above are under 1500 cc,so they all have same duty.and finding parts for these should not be a problem because they are not alone.they share market of their pair car:)
So go ahead import your dream car.but as new gen honda fit launched late in 2013,so they are newer and low mileaged just like vezels,so they are expensive in Japan.otherwise duty is same