The duo - alongside Paul Dummett - are out-of-contract at the end of the season and both have had contrasting fortunes under Howe.
Schar, a Switzerland international, has played in all-but one of Howe’s 15 games in charge, the most out of any United defender.
Longstaff, meanwhile, last featured in the 1-0 win at Leeds United after coming on as a substitute to replace the injured Joelinton.
That said, Howe is keen for both players to stay put at St James’ Park as the club embarks on an exciting young era.
Eddie Howe on Fabian Schar
When asked about Schar, Howe confirmed talks over a new deal will take place “very shortly”.
“Fabian is someone, as I’ve before, I’ve always admired,” Howe said, speaking ahead of Saturday game against Brighton and Hove Albion.
“He is a really good footballing centre-back. The most important thing for me is that he has defended very well. He is another one that is trained really well.
“We’re aware of his contract situation and we’ll be sitting down and discussing things with his agent very shortly.”
Eddie Howe on Sean Longstaff
Longstaff, after beginning the season as a regular under Steve Bruce, has played just five times since Howe arrived - only two of which have been starts.
Although Longstaff’s lack of playing time suggests otherwise, Howe has huge admiration for the Geordie midfielder and believes he has a long-term future at his boyhood club.
“I love Sean,” Howe explained. “And I haven’t probably displayed that by my team selection but that’s only because it’s a really strong area of the team. Bruno’s not playing as well.
“I really do rate Sean highly and I’m desperate for him to get an opportunity and show everyone on a consistent basis what he can do because I think he’s a top player.
“I’d love him to stay at the football club, there is no part of me that wants to see him leave.
“I believe he has a long-term future here but that’s Sean’s decision as well.
“From my side, there is absolutely every part of me that wants him to stay.”