The model is not specifically relevant for what you want to do. You don't need to extract the model or textures, unless you plan on making a custom version.
To start with, you'll need a UTC which points to the existing entry in appearance.2da (Alien_Bith_01). You can use the Taris one you extracted as a starting point, but you'll need to change a few things. The Tag and ResRef for instance. You'll also need to change the references to two module-specific scripts it uses, OnSpawn k_ptar_dancer_sp and OnUserDefine k_ptar_bith_ud. You should just be able to extract those two scripts from the Taris module and rename them, then point the UTC to them. Someone else may want to check, but a cursory glance suggests they shouldn't need changing.
Then you'll need to add the new NPC (or NPCs) to the destination module's GIT, under the CreatureList. This defines the position and orientation of the NPC in the module. Depending on how you prefer to work, you may find it easier to determine the location directly in-game via an armband, or load up the module's models in Max/GMax.
You'll need to create a MOD file to inject your changes/additions into. To start with you can just brute force edit everything, but if you plan on a public release you will want to use TSLPatcher for compatibility.
That should be the bare minimum to get you going. Keep in mind that GIT edits won't work with existing saves, so for testing you'll need a save before entering the target module for the first time.