Yes indeed good sir you are correct
A mirror is opaque because you cannot see through it
The passage is centered on the theme of belonging in a certain pack or group. Buck may be a bit different from the others but as Buck tried to be like them and did what they usually do, it gathered the trust of the pack especially the leaders. To belong in a group, one should gain their trust.
Tom lied to Myrtle by spreading around a rumor that Daisy is a catholic which would make it hard for him to divorce her and unable to marry Myrtle