Yes, you are correct - I agree that it is too early speculate given the small amount of data we have. However I would point out that here there very few multiple burials, vast majority are single graves and the dead have been properly honoured. We do not have a mass dump of victims in a shallow scraping which is more typical of Plague scenes and whilst they might flee initially, the village continues to be occupied for over a 150 years later.The Gaul argument probably derives ultimately from Gregory the Great's written account of the spread of the plague and the fact that Gaul is close to Britain. If we accept Halsall's concept of southern and eastern England being part of a North Sea zone in which ideas (as wella s goods and people) went both ways across the Channel, such a conclusion makes sense.
Bear in mind that at Edix Hill, the cemetery was in use for a long time and only about 15% of the graves have been examined. If the findings of the paper are representative of the cemetery as a whole (and they may or may not be), the actual number of plague victims would be significantly higher than the four currently identified. We have plenty of contemporaneous (and lurid) accounts of the impact of the plague around the Mediterranean, so I'd be careful about assuming that the impact was any lighter here.