Southgate paired Rice alongside Kalvin Phillips as holding midfielders while Kane led the attacking frontline with Raheem Sterling and Phil Foden in Sunday's clash against Croatia.
Sterling scored in the second half for England as the Three Lions secured three points from their Group D match at Wembley.
Both Kane and Rice impressed for the Three Lions and Southgate is likely to start the pair for England's clash with Scotland on Friday.
Speaking ahead of the Scotland match at Wembley, Neville has insisted that Kane was "undroppable in this England team."
The 46-year-old Manchester United legend added that Rice is "pretty much up there" with the Tottenham striker as an undroppable player for England.
Neville told Sky Sports: "I said last night that I felt Harry Kane was undroppable in this England team, I'd put probably Declan Rice, it seems quite a strange statement to make, but pretty much up there at this moment in time.
"He's going to play every single game, Declan Rice. I think Kalvin Phillips now, with the way he played in the first game, is going to play alongside him.
"I don't see Gareth Southgate changing that. They've got a good partnership.
"They've got good rotation in midfield. They pass well together, they play well together and they're certainly further ahead in their fitness than Jordan [Henderson] is at this moment in time."
The England boss deployed Atletico Madrid right-back Kieran Trippier at left-back ahead of Ben Chilwell and Luke Shaw.
Borussia Dortmund star Jadon Sancho was also left out of the England squad for the win over Croatia.
However, Southgate insisted that there is a "downside of a squad of 26" after some England stars failed to make the starting XI.
The 50-year-old explained: "This was the downside of a squad of 26 -- to have to have conversations with boys that don't deserve to be left out.
"But we've got to cover certain positions and for this game we went a certain route with Tripps at left-back.
"Everybody knows the competition for places in those attacking areas. So through no fault of their own we have to make a decision somewhere along the line and whoever we did that with is going to be a very good player who didn't deserve it."
Featured Image Credit: Sky Sports/PA
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