The Goodison Park club are reluctant to lose their key players so close to the end of the transfer window, and Toffees chairman Bill Kenwright is doing his utmost to fend off United, who seem intent on landing the Everton duo.
However, Kenwright is playing hardball and is attempting to price Baines and Fellaini out of a move to Old Trafford - though the club are willing to negotiate a deal for the latter.
Fellaini has told boss Roberto Martinez of his intentions to secure a move away from the club within the next three days, while Manchester United remain keen to tie up a deal before the transfer deadline.
If United submit a renewed bid which comes close to matching Everton's £25 million price tag, the Toffees are reportedly set to back down and grant Fellaini his exit desire.
However, Everton remain keen to hold onto Baines, despite the 29-year-old wanting to make the move to Manchester United too, and are hopeful that the Red Devils will end their pursuit of the England left-back having been informed of his revised asking price.
David Moyes' attempts to land two of his former charges has riled Everton officials, and interest from the Old Trafford club has forced Martinez to plan for the worst-case scenario - losing Baines and Fellaini to Manchester United before September 2.
Those plans involve a possible reunion with Wigan's James McCarthy, as well as bids for Manchester City's Gareth Barry and Blackpool's Tom Ince.