Fellaini and Baines played 90 minutes in Saturday's goalless draw with Cardiff, and Blues boss Roberto Martinez had no hesitation in including them despite reports United are set to launch a fresh bid to reunite the pair with former manager David Moyes at Old Trafford.
Should they leave, Everton have been linked with moves for Wigan's James McCarthy, Manchester City's Gareth Barry and Chelsea left-back Ryan Bertrand.
And Osman believes Everton will be strong enough to cope without them.
"As with any team, no player is bigger than the club. If someone goes, you move on, you adapt, you find new ways of playing without those players," said the midfielder.
"You will end up getting new players in who will make you stronger in different areas. Whatever happens come Monday night or Tuesday morning, we will move on and make ourselves strong."
But the 32-year-old would certainly prefer to see Baines and Fellaini remain in blue beyond Monday night.
"I will just turn the telly off on transfer deadline day and hope they're still here come Monday night," he said.
"You certainly don't want to lose your better players and you hope you sign some good ones as well.
"As players, we can't affect it, so we've just got to let things happen and deal with them when they do.
"Every Evertonian is hoping they stay, but we live in the real world and things happen differently than you want to.
"It's always difficult when you're talking about the money which is being bandied about by the clubs that are interested.
"It's going to be difficult, but we're a big club ourselves. Let's see what happens come the end of the window."
Of Baines, he added: "I think for the last few seasons he's been consistently brilliant week in, week out.
"He deserves the plaudits he gets and it doesn't surprise me that people are interested in him."