New Beast Bodies meshes well enough with the vanilla heads, and there's http://www.nexusmods.com/morrowind/mods/43110/?, of course, which meshes with New Beast Bodies. But I've not been able to find an Argonian head and hair replacer (not additional player heads), and the Pluginless Khajiit Head Pack doesn't replace Khajiit hair (although it does include a texture which is a higher-resolution version of TX_B_N_Khajiit_M_Hair01).

Considering the usual distance at which one sees NPCs and the player, I don't think a mesh replacement for Argonian heads and beast race hairs is necessary, though their lower resolution stands out among other replacers, particularly the Khajiit mane and mullet/ponytail haircut.

I heard that there was some kind of higher-res Argonian head replacer, but investigating, the sites which hosted it is dead and the link long expired.

If there's anything which also gives the Argonian vampire heads glowing eyes like Westly's vampire heads and the Pluginless Khajiit Head Pack, that'd be nice, too.