First-team coach Kristian O'Leary and head of goalkeeping Martyn Margetson, who were part of former boss Alan Sheehan's coaching staff, will remain in their roles.
Medeiros – who the club say will arrive in the "next few weeks" - was assistant to Matos at the Portuguese second-tier side, while Mendes is an experienced coach and Ricca is an analyst and coach.
"We are very pleased to be able to confirm these appointments and provide further detail on the make-up of our football staff," said Swansea chief executive Tom Gorringe.
"I also want to place on record my thanks to everyone involved in helping us as we advanced through the various required processes.
"As stated previously, this was something that we always knew we would need to go through, and we are delighted to have added this additional support for Vitor ahead of a busy run of fixtures.
"We are also grateful for the continued support of the existing staff in Martyn Margetson and Kris O'Leary, as well as that of Joe and Leon, which has been invaluable for us as a club."
Aside from Medeiros, Matos now has his full coaching team in place going into Friday's Championship game against Wrexham (20:00 GMT).