Kefu resisted the temptation to tinker with a side that looked rusty in their comprehensive 59-16 loss to Ireland first time out, though Coleman, who played for Australia from 2016 to 2019, comes onto the bench.
He twice featured against the Scots in a Wallaby jersey, winning 23-22 at Murrayfield in 2016 but then losing 19-24 in a surprise result in Sydney a year later.
A change to World Rugby's eligibility laws in 2021 allows players to change allegiance to a country with which they had links through their heritage.
Tonga also have four former New Zealand internationals in their team – full back Charles Piutau (31), centre Malakai Fekitoa (31), scrum half Augustine Pulu (33) and number eight Vaea Fifita (31).
Fekitoa is aiming to become the second player after Frank Bunce (Samoa and New Zealand) to score for two different countries at a World Cup.
The centre bagged tries for New Zealand against Namibia and Georgia at the 2015 tournament.
William Havili (25) keeps his place at fly half after Otumaka Mausia (26) was ruled out of the remainder of the tournament with a calf problem, and Patrick Pellegrini (24) comes onto the bench as the back-up number 10.
Solomone Kata (28) and Afusipa Taumoepeau (33) have switched wings for the contest, with Pita Ahki (30) to partner Fekitoa in the midfield.
Sione Talitui (25) and Tanginoa Halaifonua (27) are the two flankers in the back row with number eight Fifita, while Leva Fifita (34) and Sam Lousi (32) make up the lock pairing.
Captain Ben Tameifuna (32) is at prop with Siegfried Fisi'ihoi (36), and they will have hooker Paula Ngauamo (33) between them.
Tonga have won one of their previous five meetings with Scotland, a 21-15 success in Aberdeen in 2012.
