Samir Nasri has revealed he is ready to open talks with Manchester City about extending his stay at the Etihad Stadium.
Blackburn have signed young defender Michael Keane on loan from Manchester United for the remainder of the season.
Centre-back Hall, 21, and midfielder Luongo, 20, arrive from Tottenham on season-long loan deals while highly-rated Portuguese winger Reis has penned a two-year deal with a further 12-month option.
Hall joined Spurs from Brighton last summer but is yet to make his first-team debut for the Premier League side, while Luongo is no stranger to the Robins having enjoyed a brief loan spell at the County Ground towards the end of last term.
He enjoyed nine appearances for Town and scored twice, including the opener in the Wiltshire club's play-off semi-final first leg against Brentford.
Reis, meanwhile, predominantly operates down the left flank and will look to add a fresh attacking dimension to Swindon's push for promotion next term.