Wales are in a horrendous losing streak of 12 games and need to eke out a win from an intimidating set of Six Nations fixtures
Wales have not won a Test match since the 2023 World Cup.
Ireland are favourites to complete another title success, despite Farrell temporarily handed the reins to defence coach Simon Easterby.
Wales are largely written off as Six Nations contenders after a record losing run.
Warren Gatland is shy of quality in some areas but the Wales coach's Six Nations picks must deliver if he is to keep his job.
Edwards and Scarlets wing Ellis Mee are the Test rookies among a 34-strong group.
Experienced English lock Will Spencer has been added to the Ospreys' squad ahead of their European Challenge Cup match against Montpellier this Saturday.
Warren Gatland's wish for more muscular players will not be quickly - or easily - satisfied.
Wales and Ospreys second-row Adam Beard is in a race to take part in the Six Nations next year.
No one is expecting Wales to beat South Africa but the performance will go a long way to proving Gatland retains the faith of his players