Everton had been seeking to sign a new centre-back on deadline day, with Mina their top target.
It follows a window which saw them offer under the odds for Harry Maguire and Jerome Boateng, about whose fitness they had reservations, while they refused to meet the demands of Yerry Mina's agent and didn't even register an offer for Spurs' Alderweireld.
Everton will pay 2.6 million euros for the year's loan.
"FC Barcelona would like to publicly express their thanks to Yerry Mina for his commitment and dedication and wishes him all the best for the future".
Mina will cost Everton £34million while Gomes looks set to join on loan.
Barcelona have a buy-back option on the Colombia worldwide, who scored three goals at the World Cup this summer.
In terms of the Portuguese player, his situation is different as he does not fit into Ernesto Valverde's plans for next season and Barcelona have been keen to move him on since the beginning of the summer.
The Everton manager also let Ashley Williams leave the side on loan to join Stoke City and Ramiro Funes Mori was allowed to join Villarreal.