I'm getting ready to place an order myself. I've ordered hops from the US a couple of times with no issues whatsoever. The boxes cleared customs same day, and they clearly say "hops for brewing" on the manifest. They arrived in 8-10 d (mail seems to go much faster in the opposite direction). Only down side is I had to pay $60 in shipping to get 5 lbs (no additional customs fees were requested), but with the yen as strong as it is and the dollar generally weak lately, it's not that bad compared to the prices at the two places I know here. Certainly the selection and freshness is MUCH better.
Not sure about the legality. I'm sure you're only brewing beer with <1% ABV like I do .