Lenglet will move to the Catalan club on July 1 after Barca pay his €35m release clause.
He is expected to sign a five-year contract as Barcelona seek to strengthen their backline, with speculation over the future of Yerry Mina.
However, the 23-year old will be competing for a place in the starting line-up alongside Gerard Pique and Samuel Umtiti.
New Partenopei boss Carlo Ancelotti has apparently contacted the 32-year-old Standard Liege shot-stopper’s representatives about the possibility of a move.
Ochoa, who famously kept a clean sheet for the Mexicans during Sunday’s shock Group F victory over defending World Cup champions Germany, now has a string of admirers chasing his signature, including West Ham.
But Napoli are thought to be the frontrunners to clinch a deal for the experienced goalkeeper and view him as a ready-made replacement for Reina.
The former Liverpool man is set to join AC Milan on a free transfer this summer after his contract expires at the Stadio San Paolo at the end of June.
Monaco have signed teenager Willem Geubbels from Ligue 1 rivals Lyon in a £17.5m deal.
The 16-year-old striker made two substitute appearances for OL’s first team last season, becoming the first player born in the 21st century to play in France’s top league, but scored six goals in 12 National 2 matches.
Geubbels, who turns 17 in August, told Monaco’s official website: “This is a club with a great history that plays in the Champions League and challenges for the Ligue 1 Conforama title every year.
“The club’s project is ambitious and built on developing young talent. I can’t wait to meet my new team-mates and start learning from them.
“I’m ready and determined to help the team achieve great things.”
Monaco’s vice president and CEO Vadim Vasilyev added: “Willem Geubbels’ arrival is part and parcel of our aim to bring through the best European talents.
“Willem has already shown plenty of qualities and his great potential. With patience and a lot of hard work, we are convinced he will make it to the top.”