The French club are in advanced talks for centre-back Ozkacar, 19, a Turkey under-21 international.
At the same time, sporting director Juninho is working on a deal for highly-rated Pellistri.
His club Peñarol are currently refusing to budge on his €9m release clause, with OL wanting a reduction.
Pellistri, who has a Spanish passport, has already made 25 appearances for the Peñarol first team.
Lyon also hope to sign an established central defender and experienced defensive midfielder this summer.
Gustavo is playing for Fenerbahce but has had some ‘salary concerns’ at the club so could be available.