Gomes, who won the European Championships with Portugal in 2016, has found regular first-team football hard to come by at the Nou Camp since joining the Catalans in a big-money move from Valencia in 2016.
Mina, who impressed for Colombia at this summer's World Cup, had been pursued hard by the Blues since his exploits in Russian Federation.
The La Liga champions confirmed Mina's move for a fee of around £27 million, saying they had an option to buy him back.
Everton had a dramatic end to the window, also wrapping up deals for Brazilian playmaker Bernard and Andre Gomes, the Portuguese midfielder who had also been at Barcelona.More news: Tiger Woods battles inflammation ‘everywhere’ this week at PGA Championship
Everton, who finished eighth in the Premier League last season, have always been viewed as the side most likely to mount a challenge to break into the illustrious top six. It is the best league in the world.
New Everton defender Yerry Mina says that he is looking forward to the challenge of competing in the Premier League.
"I have spoken a lot to the coach and I know his passion for Everton and determination to be successful".
The Brazilian said new Everton boss Marco Silva convinced him to join the Toffees.
'The manager made me feel confident I wanted to play here because of what he's done in the past.
Moments later they also confirmed that Portugal global Gomes would join the Premier League side on loan.