Alonso is a horrible defender but a good player. Reminds me of Kolarov quite a bit, cannon of a left boot and always looks happier the farther away he is from his own goal
Jorginho gets through his fair share of tackles and interceptions, but I'd agree that his primary role is with the ball rather than without it. He occupies defensive positions a lot of the time, I think we can agree on that
Kovačić is a bit like Bernardo in our team. Works really hard, protects the football magnificently, is positionally very intelligent, but doesn't get the headline assist and goal numbers. I agree that he's an extraordinary dribbler in tight spaces. I think he's maybe your most underrated player
Kolarov is a very good comparison. You always felt you could get at him, but you'd also always have to worry about him popping up in your box with a crucial goal. Both Alonso and Kolarov are superb dead ball specialists too.
Jorginho is a specialist. He fulfils a specific role. Yes he gets through a lot of tackles and interceptions but I think that just comes with the territory. You can't play in that area of the pitch without getting stuck in without the ball.
I agree that both Kovacic and Jorginho occupy defensive areas a lot of the time but I guess I'd say their roles aren't specifically defensive. It's why I'd class them as midfielders who's best attributes are attacking attributes. Neither of them would be great players to have in that area of the pitch if we were playing in a back 4 for example, as proven during the Lampard period.