Uche arrives back in Spain, where he previously enjoyed spells with Almeria and Espanyol, from Qatari club Al Rayyan.
Meanwhile, Ramis returns to his homeland after a three-year spell with English Championship club Wigan Athletic.
Both players have signed 18-month deals with the Valencian club.
Levante currently sit in the relegation zone in the Spanish top flight having scored just 13 goals in 20 games.