Brooks, 20, has enjoyed a very encouraging start to life in the Championship and recently earned a call-up to the Wales senior squad.
Koeman is under pressure after overseeing a dreadful start to the campaign, but says Farhad Moshiri et al are still fully behind him and the team.
Adrian wants to leave West Ham United in the January transfer window to boost his hopes of playing for Spain at the World Cup.
Onyekuru has been in fine form for Anderlecht so far this season and will remain there for the rest of the campaign, according to his representative.
Lyon will be missing five first-team players for their Europa League Group E trip to Everton on Thursday night, with striker Mariano Diaz a key absentee.
McCarthy seems to have all but overcome the knee problem that has seen him miss the start of Everton's dreary campaign.
Everton are struggling to score goals or play with any cohesion after a transfer window that left them overloaded in some areas but severely lacking in others.
Brooks has started three Championship matches for Chris Wilder's side this season and was recently called up to Wales' senior squad.
Mirallas has barely featured for the Toffees this season but was a lively substitute against Brighton and Hove Albion.
Toffees managed to steal a point against Brighton and Hove Albion on Sunday, but failed to show any signs of improvement on the south coast.
Southampton earn first point at home since August, while Everton need a last minute penalty to salvage a point at Brighton.
De Telegraaf, a Dutch newspaper which Koeman provides columns for, recently said the Toffees boss is one of the main candidates for the Netherlands vacancy.
Everton tied the Congolese midfielder down to a new two-and-a-half year contract on Thursday (12 October).
McCarthy has been blighted by injury problems over the last year and has been at the centre of a club vs country battle in recent months.
Koeman has come under a considerable amount of pressure due to his side's poor start to the new league campaign.
Everton should have anticipated the departure of Romelu Lukaku and signing Fernando Llorente ahead of the summer transfer window, insists Peter Reid.
Everton's major shareholder Moshiri came in for criticism for his recent comments, and Reid was disappointed by the British-Iranian's statement.
Everton boss Ronald Koeman is still on the lookout for a new focal point in attack after failing to adequately replace Romelu Lukaku in the summer.
Olivier Giroud believes he made the "best choice" in opting to stay at the Emirates Stadium rather than become Romelu Lukaku's replacement on Merseyside.
Barcelona's out-of-favour defender Thomas Vermaelen has revealed that the La Liga giants blocked his departure during the summer transfer window.
Everton and West Ham are keeping tabs on Theo Walcott who has played only 46 minutes of Premier League football this season.
Injury-plagued 26-year-old could play against Moldova and Wales despite having yet to feature at club level in 2017-18 as he recovers from a knee issue.