It is just that Tamans are spawned (only in light armor), but ortnoks are not spawned in any armor when playing skirmish for example...
But when changing the definition to:
models {
neutral {
aliens/ortnok body01 head01 0
aliens/ortnok body01 head02 0
aliens/ortnok body01 head03 0
aliens/ortnoklight body01 head01 1
aliens/ortnokmedium body01 head01 2
}
You will suddenly see different kinds of (high-resolution, good looking) Ortnoks on the battlefield in Skirmish Mode...
Also the definition for Taman Medium Armor in team_aliens.ufo is missing:
aliens/taman body01 head01 2
I hope that helps you to understand, sometimes I feel like speaking Chinese language here