Not trying to be opposite to the general thoughts but I donīt think Ron will be Quidditch captain. Harry deserves that position much more then Ron and also my mind always goes to the scene where Harry asks Dumbledore why HE wansīt made prefect and Dumbly tells him itīs because he thought Harry had a lot to deal already. That means: Harry wanted to be prefect and Iīm pretty sure he would like to be quidditch captain. Ron has only been in the team since book 5 and Harry has been there since book 1!
But I do think Ron can make his way into Head Boy.
I think Krum paying a visit would be better because all we need is to make a wake up call on Ron. Hermione knows her feelings for him for quite some time, but Ron, even tough he feels the same, he doensīt think about it and actīs really clueless. Last time JK made him act foward was because of Krum (Yule Ball
) and now would be a good time to use that excuse.