I agree. Multiple bodies would suit, but I'd use OPEN-bodies and surfaces for more complex geometry (Thicken or Close in Part Design at the end). Blade geometry, I suspect, would suit either Circular or Conic Sweep, or perhaps a Loft with pre-defined section profiles for better control...
Yes, JT can be exported from V5, but I believe an additional licence is required- probably from either UGS or Theorem. It is UGS that supply the V4 > JT translator in Catia V4. I am curious WHY you would want to do this? [ponder]