The names are interchangeable to some extent, and Mylrea is a nightmare when researching via the internet because it is often transcribed as Mybea and other weird variant spellings! From memory Mylroi/Mylroie seems to be way the name was recorded in the 1880s, particularly on the east side of the Island i.e. Laxey/Lonan. This may be down to an individual enumerator deciding on his own unique spelling! I don't know if the name generally stays spelt this way or whether it reverts back to Mylrea...