Is anyone researching the Cottier family, esp of Lezayre?

I have the following:

1851 Census 5 Bolton Street, Liverpool. HO 107 / 2192 fol.409
William Cottier Head Mar 31 Joiner Isle of Man
Jennet do Wife Mar 36 do do
Samuel do Son 6 Lancashire L'pool
William do Son 4 Isle of Man
Margret do Daur 2 Lancashire L'pool

The 4yo son William was baptised in Lezayre in 1846 and this gives me the connection to Lezayre.

Although it is rather an assumption on my part, I have William, father of this family, baptised 24 June 1821 Lezayre s/o William Cottier & Margaret Kinread/Kinrade.

Jennet/Janet Cottier was bn Qualtrough bpt 1820 Rushen, d/o Rev Joseph Qualtrough & Agnes McCullock. Rev Jos Q was vicar of Lonan 1824 till his death in 1853.

There is a possible marriage for Margaret Eliza Cottier to James Underwood at St Bride with St Saviour, Liverpool in 1876. but again an assumption.

What happened to Samuel James & William Joseph? Also where did William Snr & Jennet die?

I am looking for information on what happened to this family post 1851 census, Lpl. Also of course, contact with any descendants.

Any assistance most appreciated.

Elizabeth