It's so long since I read the Canterbury Tales in full that I wouldn't venture an opinion on this, but I would point out that Chaucer is often very ironical and that, even when he appears to be presenting a character favorably, there is the possibility that he means something quite different. The Knight is a case in point. Quite a few years ago a book was written about the Knight (I can't remember title, publisher or year but I'm pretty sure the author was Terry Jones) which checked out all the places where the Knight served in the cause of the faith. I think every single one of them was a byword in Chaucer's time for sheer brutality and greed on the part of the crusaders, so Terry Jones at least was convinced that the glowing introduction that Chaucer gives to the Knight is in fact bitterly ironical and that he is nothing short of a rogue and impostor. In the case of other characters too, such as the Prioress, subtle little hints suggest something different from the outward picture, so I would advise caution when trying to list Chaucer's own favourites.
The General Prologue, where Chaucer introduces the pilgrims, is the best place to determine Chaucer's opinion of most of the pilgrims. There is no doubt Chaucer likes the Knight, the Oxford Cleric, and the Parson. There are others he admires in some ways, but he is completely favorable in his descriptions of these three. He likes the Knight because the Knight's character represents all a Knight is supposed to represent: "truth, honor, generousness and courtesy". The Oxford Cleric is another of Chaucer's preferred pilgrims. The Cleric is liked because he is what a student should be: he is serious about his studies, he is not worldly, he didn't babble needlessly. He was thin (not gluttonuos), he was moral, and he loved learning and teaching. The Parson is one of the very few clergy members that Chaucer liked. Most of the clergy is described with much sarcasm and disdain, but the Parson, because he is honest, pious, and unworldly is described in a positive way. Chaucer says the Parson preaches the gospel and shuns worldly possessions, giving what he has to the poor. He says the Parson is a true example of what a member of the clergy should be. The Parson leads the type of life that he preaches to his parishoners that they should lead. He is not a hypocrite as are most of the other clergy in the tales. In general, Chaucer favors people who are honest and not hypocritical.
Chaucers 3 favorites would have to be the knight, the parson and the Sergant of Law because he feels that they are the realist and trustworthy and that they have the right qualities while all the others sit there and lie and scam they are the ones with the true and purest heart
The Pardoner, The Squire, The Yeoman. And you are not a teacher so do not set tasks.