Gelling is rare in Maughold & Lezayre. One family was Thomas Gelling, a Miller at Cornah Mill Maughold. He was born Douglas 1810 and married Agnes Brough 18 May 1839 Lezayre. They lived there a long time, until their deaths in 1893 (Tho) & 1890 (Agnes). Their first child was Mary Ann bp 22 Sep 1839 Lezayre., and she was buried 6 Feb 1861 Maughold age 21 That covers the Mary Ann from your earlier message.
The Mary Ann Gelling age 14 in Lezayre with grandfather Robert Corlett is an illegitimate daughter of Richard Gelling and Mary Ann Corlett (d/o Robt), bapt 25 Sep 1836 Braddan. In 1841 she is Mary Gelling 5, with Robt Corlett 64 Mariner, Mary 26 and other younger Corletts, at Back Street in Douglas. There are two or three choices of who Richard Gelling would be, including the Iron Founder b 1812 who married Nessy Howard in 1837 Ballaugh.
I've tried to tie Edward Gelling to any of these other Gellings, but no luck.
To answer the other question that the 3 July 1836 Maughold daughter of Edwd Gelling & Margt Stowell was baptized "Mary Ann", this is true. However, in 1841 she is "Margt Gelling" age 4 listed at the top of the servant list in "Rachail Looney" age 54's household at High Bawnian? Cottage, Maughold, and she is "Margaret" from then on. The Maughold transcription by Tom Corteen also says "Mary Ann" (complements Sue 29 Jul 2012). I can't explain this, other than "Mary Ann" and "Margaret" sometimes are confused when the writing isn't very good.
My last thought here was whether the 4yo Margaret Gelling being with Rachel Looney (als Redhead), wife of John Looney b 1788 could be a useful clue to solve the Looney dilemma discussed at length in this and other threads. But it doesn't help. No question she's a great-granddaughter of John Looney & Isabella Camaish md 1788 Maughold, but the big question is who are the parents of this John, ie, is he the son of John Looney (1770 will) & Margaret Kelvie, or the grandson through son Daniel? Averil says the latter, Larry (and others?) think the former. After many hours trying to understand what's been said, I see some problems identified with every combination. I'm sure glad I'm not on this jury.