Copies all avatar components and children to another object. Such as Dynamic Bones, Guns, Animations, etc.

CopyAvatarData.cs

#if UNITY_EDITOR
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEditor;
using System.Text.RegularExpressions;

public class CopyAvatarData : ScriptableWizard {
	public GameObject from;
	public GameObject to;
	bool finished;
	enum Options { AvatarDescriptor = 1,
				   DynamicBones = 2,
		           Animators = 4,
		           LooseGameObjects = 8
	};
	Options selected;
	public CopyAvatarData() {
		finished = false;
	}

	Component CopyComponent(Component original, GameObject destination) {
		System.Type type = original.GetType();
		Component copy = destination.AddComponent(type);
		// Copied fields can be restricted with BindingFlags
		System.Reflection.FieldInfo[] fields = type.GetFields(); 
		foreach (System.Reflection.FieldInfo field in fields)
		{
			field.SetValue(copy, field.GetValue(original));
		}
		return copy;
	}

	[MenuItem("VRChat SDK/Copy Avatar Attributes to Other")]
	static void CreateWizard() {
		CopyAvatarData wiz = ScriptableWizard.DisplayWizard<CopyAvatarData>("Transfer Avatar Data");
	}

	// Ensures that game object to and from have an identical hierarchy with the same components and the same properties on the components.
	void CopyComponents( string current, GameObject obj, Options flags ) {
		GameObject target = null;
		if (current == "") {
			target = to;
		} else {
			Transform test = to.transform.Find (current);
			if (test) {
				target = test.gameObject;
			}
		}
		if (!target) {
			string sparent = current.Substring (0, current.LastIndexOf ("/"));
			Transform test = to.transform.Find (sparent);
			GameObject parent = test ? test.gameObject : null;
			if (!parent) {
				throw new UnityException ("Somehow tried to create child " + current + ", but couldn't find " + current.Substring (0, current.LastIndexOf ("/")));
			}
			GameObject copy = GameObject.Instantiate (obj);
			copy.name = obj.name;
			copy.transform.SetParent (parent.transform);
			copy.transform.localPosition = obj.transform.localPosition;
			copy.transform.localRotation = obj.transform.localRotation;
			copy.transform.localScale = obj.transform.localScale;
		} else {
			foreach (Component c in obj.GetComponents<Component>()) {
				CopyComponent (c, target);
			}
		}
		for (int i = 0; i < obj.transform.childCount; i++) {
			if (current != "") {
				CopyComponents (current + "/" + obj.transform.GetChild (i).name, obj.transform.GetChild (i).gameObject, flags);
			} else {
				CopyComponents (obj.transform.GetChild (i).name, obj.transform.GetChild (i).gameObject, flags);
			}
		}
	}

	Transform RecurseFind( Transform obj, string name ) {
		Transform find = obj.Find (name);
		if (find) {
			return find;
		}
		for( int i=0;i<obj.childCount;i++ ) {
			find = RecurseFind (obj.GetChild (i), name);
			if (find) {
				return find;
			}
		}
		return null;
	}

	// Updates dynamic bone references to refer to the new avatar bones rather than the old ones.
	void ConvertDynamicBoneReferences() {
		foreach (DynamicBone d in to.GetComponentsInChildren<DynamicBone>()) {
			List<DynamicBoneColliderBase> newColliders = new List<DynamicBoneColliderBase> ();
			foreach (DynamicBoneColliderBase c in d.m_Colliders) {
				newColliders.Add (RecurseFind(to.transform,c.gameObject.name).gameObject.GetComponent<DynamicBoneColliderBase> ());
			}
			d.m_Colliders = newColliders;
			List<Transform> newExclusions = new List<Transform> ();
			foreach (Transform t in d.m_Exclusions) {
				newExclusions.Add (RecurseFind(to.transform,t.name));
			}
			d.m_Exclusions = newExclusions;
			d.m_Root = RecurseFind (to.transform, d.m_Root.name);
		}
	}

	void ConvertAvatarDescriptor() {
		VRCSDK2.VRC_AvatarDescriptor ava = to.GetComponent<VRCSDK2.VRC_AvatarDescriptor> ();
		ava.VisemeSkinnedMesh = to.GetComponentInChildren<SkinnedMeshRenderer> ();
	}

	void OnGUI() {
		EditorGUILayout.HelpBox ("This will mess with your `To` game object, it's destructive!", MessageType.Warning);
		from = (GameObject)EditorGUILayout.ObjectField("From", from, typeof(GameObject), true);
		to = (GameObject)EditorGUILayout.ObjectField("To", to, typeof(GameObject), true);
		selected = (Options)EditorGUILayout.EnumMaskPopup ("Stuff to transfer (Does nothing):", selected);
		if (from && to && GUILayout.Button ("Transfer!")) {
			CopyComponents ("", from, selected);
			ConvertDynamicBoneReferences ();
			ConvertAvatarDescriptor ();
			finished = true;
		}
		if (finished) {
			EditorGUILayout.Space ();
			EditorGUILayout.HelpBox ("Done! :)", MessageType.Info);
		}
	}
}
#endif

CopyAvatarData.cs(95,44): error CS0030: Cannot convert type DynamicBoneCollider' to DynamicBoneColliderBase'
CopyAvatarData.cs(98,20): error CS0029: Cannot implicitly convert type System.Collections.Generic.List<DynamicBoneColliderBase>' to System.Collections.Generic.List'

unity 2017.4.28f1

You need dynamic bones, sorry. I think I've updated this script too. I'll check in a sec

Does it work to copy 1 VRM model with VRMSpring bones script to another vrm model? or does the script just works for dynamic bones script only?