I don't think it is accurate to say Pulisic is "clearly 4th choice." In 5 league games, he's started 3 and made 1 sub appearance, and has more minutes than Pedro or Willian (277/180/145). It is true he did not play in the last two games, and was on the bench - Wolves in the league and the CL game against Valencia. I may be reading it wrong, but I think the reason for that has something to do with Kante being out both of those games and Lampard switching to a 3 centerback formation (with Willian next to Mount in the attacking band, behind Abraham.) I'm not writing him off so early in the season and would not be surprised to see CP start against Liverpool on Sunday if Kante is back. Mount may also be out, which creates more opportunity.
Hudson-Odoi will compete with Pulisic for minutes. I think Loftus-Cheek will be more in competition with the midfielders - Kovacic, Barkley.