Definitely not Douglas. With a 77 glove he should not be at SS. So it's down to Johnson and Cornejo.
There is no conceivable way that Cornejo comes close to those projections. He's in his 6th pro year, ansd his ratings didn't budge an inch between season 14 and season 15. He'll be lucky if he adds even one point in all those categories. That said, he will still be a very good fielding SS. Cornejo and Johnson are both good, in fact, but Cornejo is better. Johnson has a slightly better glove, Cornejo has slightly better range, but Cornejo takes it with a much stronger arm that will get a lot of extra outs for you. They'll both be poor hitters so you can rule out a triple crown for either of these guys, but both will give you great defense at SS. I'm inclined to take Cornejo because in addition to his better fielding, he also has blazing speed which will help him run out grounders and nab some extra bases, making him only mostly an offensive liability.