I checked before I posted — the big font works for me, the mixed-emojis do not. Also, the big font is terribly pixellated in wezterm, both in terms of the emoji and the text. Maybe font configuration would help :shrug:
Most terminals that supports double-height/double-width seems to just scale the bitmap of the glyphs instead of properly rendering the font at twice the scale even if the font used is a vector font, for no particularly good reason.