A bit of Black Comedy; at one point in Snow Miser's song, he once again states "whatever I touch turns to snow in my clutch" whilst approaching Jingle and Jangle. Jingle and Jangle's expressions imply that they're terrified that he's about to test this power out on them (instead, he does it to Jangle's hat, before changing it back when Jangle freaks out).
Just the idea that unlike his jovial brother, the grumpy and unfriendly Heat Miser has a song-and-dance number virtually identical to Snow Miser's.
This exchange when Mrs. Claus explains the situation to Mother Nature.
Mother Nature: So [Heat Miser and Snow Miser] gave you a hard time, did they?
Later, when Mother Nature summons the brothers to straighten things out, the two of them immediately start kissing up to their mommy; Snow Miser seems to try fixing her hair/adjusting her hat while Heat Miser appears to be trying to warm up her tea.
They also go about making rude faces at each other behind her back.
Snow Miser's line: "Hold it. Hold it! Hold! It!"
A Miser Brothers Christmas:
Heat Miser growling at a rabbit.
When they witness Santa getting injured, the Miser Brothers' response is to both say in unison "Mommy's gonna kill us!"
The Greenland/Iceland argument.
Heat Miser: There's hardly any ice there at all!
Snow Miser: You did the same thing, but with Greenland! Greenland's covered in ice! It's not green!
Heat Miser: It will be when I'm done with it!
Snow Miser: Over my melted body!
Heat Miser: I can arrange that!
Every time the North Wind gets angry because of his over-the-top expressions and because of how composed he tries to make himself out to be when in the presence of his mother.
When the North Wind's scheme is finally revealed:
North Wind: You two have no authority over me!
(The Miser Brothers smirk at each other)
Snow Miser: We may not...
Heat Miser: But we know someone who does...
Miser Brothers: (in unison) Oh, Mother!
(a furious Mother Nature appears in a bolt of lightning; North Wind gulps)