I incline towards the opinion that the original Scottish pronunciation was Mac Fair son, and this was modified to Mac Fear son in the U.S.   Mac Fur son is phonetic Transatlantic and is at a further remove.

As to the pronunciation of leeneia, it has no pronunciation. It's merely a screen name.

The radio show is on KKFI, Kansas City, from 11 to 1 (I think) on Sundays.