Onyekuru is the joint top-scorer in the Belgian top-flight with 22 goals in 38 games.
Sanchez, Shkodran Mustafi and Gibbs are also expected to be fit for Wembley clash.
Kroenke Sports & Entertainment say they will remain a "committed, long-term investor" in the club.
Wenger, 67, is under pressure to resign after a disappointing season.
Arsene Wenger's future at Arsenal remains uncertain with the French coach yet to agree an extension.
Gunners shoot down Toffees but fail to sneak into top four.
The 22-year-old will represent his country at the Under-21 Euros in Poland in June.
Arsenal need to beat Everton and hope Middlesbrough take points off Liverpool to make the top four.
Usmanov and Kroenke hold 30% and 67% stake, respectively at Arsenal.
Lacazette has scored 20-plus goals in Ligue 1 in the last three seasons.
Both Ozil and Sanchez are out of contract at the end of next season.
Sanchez will enter the final year of his contract at the end of the current campaign.
David Ospina has made only 13 appearances this season.
Boss ruled out to sign a new goalkeeper during the coming summer transfer window.
Chile international scored a brace to keep alive the Gunners slim hopes of finishing in the top four.
Holding has impressed since being thrust into Gunners first team in recent weeks.
But Gunners boss does expect rivals Manchester City and United to spend big in the off-season.
Kolasinac will be a free agent when his contract with Schalke expires on 30 June.
Koscielny will miss his side's game against Sunderland in order to be fit to face Everton and Chelsea.
Bellerin is reportedly open to the idea of leaving Arsenal for Barcelona in summer.
Szczesny has spent the last two seasons on loan with the Serie A club.
Sanchez's contract at the Emirates Stadium runs out this summer.