score:3
No, your name in kana is not really required, it's just that the booking systems for both sites are 100% geared for Japanese people. But instead of making something up, just punch your name into Google Translate and let it do the work: James Smith → ジェームス·スミス.
That said, I wouldn't bother booking at all, the buses are virtually never full. Just show up a little early if you're stressed out about missing your flight.