Help with Exporting Blender Animations & Sharing Rigs in Unity

Hi everyone,

I’m working on a game in Unity (2018.4.20f1, I get its old, but newer versions have been trouble, and dropped support for my gamepad) and need help with character animations, particularly exporting from Blender and sharing animations across characters in Unity.

My Setup:
Blender:
- Characters use a shared base rig but have unique features (e.g., tails, wings).
- Animations work in Blender regardless of extra features (just using typical parent-child behavior for unspecified bones).
Unity:
- FBX files include: rig, skinned mesh, material, mesh, animations, and an ‘avatar’ (what is that?).
- Using generic rig type (humanoid rigs mangle animations, seem to restrict pelvis movement, and stretch limbs).

Problems & Questions:

Reusing Animations Across Characters & Rig Setup.
Problems:
- I need animations to work across characters with unique features (tails, wings, etc.).
- Humanoid rigs allow sharing but mangle animations and seam to restrict pelvis movement.
- Generic rigs preserve movement but don’t seem to support animation sharing.
Questions:
- Should I use a base rig with optional secondary rigs for extra bits like tails, or export per-character rigs?
- How can I enable animation sharing while preserving proper movement for unique features?
- Is there a way to get this to work with the generic rigs? or if the humanoid one is needed, Is there a way to fix humanoid rigs to allow full pelvis movement and all the other weirdities?

Blender Export Workflow & Animation Setup:
Problems:
- I’m unsure how to set up animations and rigs in Blender for Unity compatibility.
- The FBX export process (e.g., actions vs. NLA tracks) and required settings confuse me.
Questions:
- What are the best practices for rig setup in Blender (e.g., root bone placement, extra features)?
- Should animations be saved as Actions or NLA strips or something else for Unity?
- What are the proper FBX export settings for Blender → Unity to ensure animations work correctly?
- Where can I find the Blender menu for managing animation exports?

General Questions:
- How do you rig/animate characters with shared rigs and unique meshes for Unity?
- Any tutorials/resources for Blender-Unity animation workflows?

Thanks in advance for any help or resources! I’d love to learn from your experiences.