Mbabu was sold by Newcastle for a nominal fee last summer.
FC Basel have turned down the chance to sign Leo Lacroix permanently, giving Everton the chance to bring the defender to the Premier League.
Basel winger Mohamed Elyounoussi could head to the Premier League with Arsenal, Southampton, Leicester City and Huddersfield Town linked.
Premier League duo West Ham United and Southampton watched Basel's Elyounoussi in the Champions League, but the Hammers now have another target.
Premier League duo Tottenham Hotspur and Everton have both sent scouts to watch FC Basel in Champions League action this season.
Scottish Premiership champions Celtic failed to sign Mohamed Elyounoussi but now Premier League trio Arsenal, Southampton and Leicester City are keen.
Celtic have been linked with three Ghanaian goal machines in recent months but not Raphael Dwamena.
Reto Ziegler hinted that he would jump at the chance to join Celtic while Leeds United were also linked with the Swiss defender.
Benjamin Kololli is attracting attention from the Bundesliga and Ligue 1 but Queens Park Rangers remain hopeful they can lure him to Loftus Road.
Leeds United have been linked with a move for Ezgjan Alioski of Lugano in the summer transfer window.