From the 1841 Census returns for Breasclete in the parish of Uig:
Donald Maciver 40 Small tenant Henrietta35 Ann15 Mary14 Philip10
As you can see, Annappeared, aged "15", in the 1841 Census returns. Although you should bear in mind that in the 1841 returns, ages of those aged 15 and over were rounded down to the nearest multiple of 5, she could have been anything from 15 to 19 years old, though, given the stated ages of her siblings, it looks as if she was indeed probably 15 or 16, and would have been born, therefore, some time around the years 1824 to 1826. Unfortunately there is no record of her birth or even a baptism. The recording of births (baptisms) and marriages did not begin in that area of Lewis until 1824, and, as there was no legal requirement to register births at that time in Scotland, her birth was not recorded. Ann, it would appear, did not marry. She appears, aged 56, in the household of her widowed mother Henrietta, aged 80, at Breasclete in the 1881 Census returns for the Registration District of Carloway (RD 086B, Enum. Dist. 1, Page 20). Ann's nephew, Donald Maciver, aged "23" (but actually born 2 April 1859 to Finlay Maciver and Ann Macarthur), is in the household with them.
The 'Philip' who appears in the 1841 Census returns for that household is indeed Finlay. Unfortunately, you will find occasionally within Gaelic-speaking areas that the enumerator will out of ignorance and crass insensitivity record names not with their traditional English equivalents (or conventional usages, where there is no one-to-one equivalence between the original Gaelic name and the English form) but with a name that is alien to the culture but which, in the enumerator's mind at least, has some similarity with an English name (in this case the 'Fi-' of Finlay and the 'Phi-' of Philip! The marriage of Mary and the marriage of her brother Finlay both took place in 1855, Mary giving her age at the time as '27' and Finlay as '25'. Note that Uig is the name of the parish and district/civil registration district, and the village is spelled in English 'Breasclete'. For your records, you can record them as born in 'Breasclete, Uig, Isle of Lewis' (though the postal address nowadays would simply be Breasclete, Isle of Lewis).