Was worried about our no number 10 situation, but realistically we don't need one. Played our best footy last season without Coutinho and the two teams we can make out of the squad are pretty darn good with plenty of pace and creativity. Think Keita will bring that added creativity as well.
ALISSON
LOVREN VAN DIJK
CLYNE ROBERTSON
FABINHO HENDERSON
SALAH KEITA MANE
FIRMINO
KARIUS
GOMEZ MATIP
ALEXANDER-ARNOLD MORENO
WIJNALDUM GRUIJC
WOODBURN LALLANA SHAQIRI
STURRIDGE
MILNER
OJO
BREWSTER
KLAVAN
ORIGI
INGS
MIGNOLET
OX (AT SOME POINT LATER NEXT YEAR)
Keita was the first choice replacement for Coutinho, this is why we were ready to pay more to get him in Jan. Coutinho was being moved in the middle though his best position was on the left wing. If Mane reaches his level 2 seasons back he will be as good as Coutinho there.
Otherwise, regarding your list, don't think Grujic will stay, if he doesn't go on loan he will probably be sold and Milner will be the back up.
My worry is no proper cover for Firmino and no top free kick taker, maybe Shaqiri as he has scored a few.