The "mybaby-name" website says that Seanell is an Irish and African American name; it is from the Irish and means "God's gracious champion", a combination of Shewn and the female name Nell.

Assuming that Shewn is a variant of Seán (= John, Hebrew "God has been gracious"), the combination with Nell [a pet name for Helen, "bright, sun-like"] makes approximate sense.