This is a good point! Harriet and Frank’s submissiveness flatters Emma and encourages her to continue advising the first for “[Harriet] knows nothing herself, and looks upon Emma as knowing every thing” (5) and surmising for the second. Frank did disagree with Emma about Jane Fairfax’s complexion (24) but I think it was a disagreement rather agreeable to Emma. She found Henry’s submission to all her suspicions of Jane “a compliment to her penetration which made it difficult for her to be quite certain that she ought to have held her tongue” (27). I don’t think Frank’s influence is any better for Emma than Harriet’s adoration and it does not help that she is certain he is in love with her. Emma’s relationships with Harriet and Frank are strengthening the real evils of Emma’s situation and she is still, despite the Elton debacle, quite unaware:

The real evils indeed of Emma's situation were the power of having rather too much her own way, and a disposition to think a little too well of herself; these were the disadvantages which threatened alloy to her many enjoyments. The danger, however, was at present so unperceived, that they did not by any means rank as misfortunes with her. (1)