Neville was already the first-team coach under Moyes, while Butt had been working with United's Under-19s and Under-21s as a technical coach.
Scholes, who retired from playing last year, has returned to the club to help out his teammates from the so-called ''Class of 92'' that was instrumental in the success of United over the past two decades.
Giggs, Butt, Neville and Scholes have made 2,453 appearances for United in total.
Moyes was fired on Tuesday after just 10 months in charge since replacing Alex Ferguson, with United languishing in seventh place in the Premier League.
Giggs was appointed player-manager for the final four games of the season pending the hiring of a full time replacement.
United plays Norwich on Saturday.