Beaumains and Gauvain: Same Origin?

Roger Sherman Loomis believes that the name Beaumayns is not just a derogatory nickname given to Gareth. He says it is a corruption of Gauvain, another spelling for the name of Gawain, the G having been misread as a B and the rest twisted into Beaumayns. It was done "probably by some illiterate Anglo-Norman, who was trying to make the epithet yield a meaning." There are many parallels between the knight Gauvain and Beaumayns--even down to the fact that Gauvain's mother was named Morcades and Beaumayns' was named Morgause (439-41). It may be that Gareth is just an offshoot of Gawain, which would explain why Gawain is so fond of him, as well as why Gareth tends to stay away from the murderous plots of Agravaine and Mordred (400).