as big of a presence as you claim.
According to the official census of Tonga, the LDS church makes up 16.8 percent of the country, a distant second to the Free Wesleyen Church of Tonga which makes up 37% of the population.
And the official census of Samoa, has the LDS church at third with 15.1%, behind Congregational Church of Samoa which has 31.8%, and Roman Catholic which makes up 19.4%... And just passing Methodist (which had been third until the most recent census).
Definitely a presence, but a distant 2nd and 3rd respectively.
I know the church itself has different numbers, but I wonder if those numbers include those who no longer identify as Mormon, but at one time did.