Smith Rowe's probably the most likely to go on loan. It seems Leipzig really want him back, seeing as injury disrupted his last spell there. He also has Mkhitaryan/Ozil/Ceballos ahead of him, even if two of them are unwanted husks.
I'd probably be most disappointed to see Saka go. He always produces something in the final third and looks the most complete and confident of the academy players despite being the youngest.