West Brom have handed new deals to a raft of young players.
Donnellan enjoyed a successful spell on loan at Dagenham & Redbridge in the National League in the second half of last season while Fitzwater impressed head coach Tony Pulis during pre-season last year.
Defender Max Melbourne, 18, and midfielder Alex Bradley, 18, have both signed new one-year contracts.
Australian under-20 goalkeeper Jasko Keranovic, 19, has signed a one-year contract with a further 12-month option in the club's favour, while fellow shot-stopper Ethan Ross, 20, has agreed a one-year deal.
Goalkeeper Brad House, 18, and forward Evan Pierce, 18, have also been offered new deals.