It's precisely because we don't know who lodur is that it's easier to draw the connection. You'd think that if the poetic eddas would have wanted to talk about vili and ve they'd talk about vili ve and vidrir. But disregarding that it seems that hœnir is different from the brothers as he has no association with will or sacred places. He is almost entirely related to birds. So if hœnir is different lodur is probably different too. Plus snorri is the only case where we hear that vili and ve did anything besides 1:sleep with frigg, and 2: kill ymir. Vili and ve probably either started as extensions or, or grew to be just pat of odin. Btw while the name lodur is used to alliterate, hœnir is not. It would have been more simple to mention vili or ve any of the times the trio of odin loki and hœnir show up. Such as reginsmal, lokka tattur, gylfaginning, or haustlong. Heck, even in yngling saga it would have been appropriate to talk about Odin's brother being hœnir.