First XI + subs:
Trent Matip Van Dijk Robertson
Salah Firmino Mane
Subs: Keita, Ox, Jota.
Without including anyone from the 14 players above we could still field a reasonaably solid 2nd team in the cup:
Neco Gomez Konate Tsimikas
Gordon Minamino Origi
That said, I wouldn't really expect a lineup against a PL team to feature all of Kelleher, Neco, Elliott, Jones, and Gordon, as Klopp tends to mix some more first teamers into the lineup in the cup to insulate youngsters a bit more. The right side with Neco/Elliott/Gordon seems particularly inexperienced too and ideally you'd add another senior player to that mix.
For instance, drop one of Henderson or Fabinho into DM to give us a strong nucleus of Gomez/Konate/DM, and push Milner and Elliott forward, and have Gordon off the bench.
Elliott Minamino Origi
That lineup looks much more solid, and we'd still be giving minutes to some fringe players along with Kelleher, Neco, Elliott, and Jones which seems about the number (3-4) of young players that Klopp is comfortable with in these types of games.