We do not actively research anymore partly since the LDS and other internet sites/transcribers with vested interests have along with others wrecked genuine Genealogy/Family History !
The real adventure is no more and social media are completing the job.
However from old Corlett files we can add the following:-
The said Robert Corlett (one of many) was a farm labourer.
He was a bachelor and she a spinster when married.
The couple were both of age.
It would only be speculation why they were married in Douglas and whether the will referred to her married name
We do not use will summaries and also beware modern transcribers notes on full wills.
Witnesses at their wedding were a Christian and a Curphey, relatives?
Additional information/children to this Robert Corlett and Elizabeth Cottier included:-
John who you mentioned could possibly be named after his Corlett grandfather
Elizabeth -we do not know!
Rob’t (born about 1805) was named after his father
The family was back in Marown by 1807!
Wm. Thos , another abbreviation
The above two being christened at the same time in 1807
Cha. (Charles) Edward was born/christened in 1809 at Mn
He was buried on 03rd Jan. 1810 at Mn
Edward his successor was born in 1811 in Mn
A huge gap here before other claimed births!
Maria born 1820 (sometimes found as Marea, hence this and other misspellings)
It was claimed on this board in 2004 that she married Thomas Stalker and they went to North America
However their were two Maria Corletts born about the same time
Jane (born 1822) was buried aged 14 on 05th May 1837 at Onchan?
Susanna (born 1839?) was another of the three doubtful’s above.
Despite a one name study we did not find the precise birth years, death/burial dates or places of either parent
Their were many Robert and Elizabeth Corletts (both as you may know, very common names) in our records.
All without a proper fit before 1779 and between 1811 up to and including the 1841 census.
We do not know if all or any of this family stayed on the Isle of Man.
Therefore more information from you on these two would help narrow things down.
It would also be interesting for you and Mike/Carol to compare how you both got to this point.