Liverpool academy product Maguire has agreed a one-year deal, while 20-year-old Sherif has signed for two years.
Maguire, 23, joined Fleetwood in January 2017 and spent time on loan with Crawley Town last season.
"Joe is a talented footballer and he has a great left foot," Stanley manager John Coleman told the club website,
"He is someone I looked at when he was at Liverpool but I did not manage to sign him and he went to Fleetwood.
"His career has been stop-start since then and this is a chance for him to kick on.
"Lamine is an exciting prospect. He turned down a couple of offers from foreign clubs as he believes he can make his mark in England."