HoloLens: Using Unlit / VertexLit Shaders with Particle System

Question

Context: Drawing Graphs on HoloLens via Unity Particle System.

For drawing complex Graphs on Microsoft HoloLens (see my Answer https://stackoverflow.com/a/46073583/5707551) i want to use the VertexLit/Unlit Shaders to increase the frame rate

But if i try to access the color via

void Update()
{   
   //...
   for (int i = 0; i < points.Length; i++)
   {
      Color c = points[i].GetCurrentColor(GetComponent<ParticleSystem>());
      points[i].startColor = c;
   }
   //...
   GetComponent<ParticleSystem>().SetParticles(points, points.Length);
}

with this Shaders the color of the particles does not change.

It worked fine with the default or the FastConfigurable Shader.

Does anyone know what I must consider when using these shaders?

Edit - Shader Properties:

Shader "HoloToolkit/Vertex Lit Configurable"
{
    Properties
    {
        [Header(Main Color)]
        [Toggle] _UseColor("Enabled?", Float) = 0
        _Color("Main Color", Color) = (1,1,1,1)
        [Space(20)]

        [Header(Base(RGB))]
        [Toggle] _UseMainTex("Enabled?", Float) = 1
        _MainTex("Base (RGB)", 2D) = "white" {}
        [Space(20)]

        // Uses UV scale, etc from main texture
        [Header(Emission(RGB))]
        [Toggle] _UseEmissionTex("Enabled?", Float) = 0
        [NoScaleOffset] _EmissionTex("Emission (RGB)", 2D) = "white" {}
        [Space(20)]

        [Header(Blend State)]
        [Enum(UnityEngine.Rendering.BlendMode)] _SrcBlend("SrcBlend", Float) = 1 //"One"
        [Enum(UnityEngine.Rendering.BlendMode)] _DstBlend("DestBlend", Float) = 0 //"Zero"
        [Space(20)]

        [Header(Other)]
        [Enum(UnityEngine.Rendering.CullMode)] _Cull("Cull", Float) = 2 //"Back"
        [Enum(UnityEngine.Rendering.CompareFunction)] _ZTest("ZTest", Float) = 4 //"LessEqual"
        [Enum(Off,0,On,1)] _ZWrite("ZWrite", Float) = 1.0 //"On"
        [Enum(UnityEngine.Rendering.ColorWriteMask)] _ColorWriteMask("ColorWriteMask", Float) = 15 //"All"
    }

    SubShader
    {
        Tags { "RenderType" = "Opaque" "PerformanceChecks" = "False" }
        LOD 100
        Blend[_SrcBlend][_DstBlend]
        ZTest[_ZTest]
        ZWrite[_ZWrite]
        Cull[_Cull]
        ColorMask[_ColorWriteMask]

        Pass
        {
            Name "FORWARD"
            Tags { "LightMode" = "ForwardBase" }

            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag

            #pragma multi_compile_fwdbase
            #pragma multi_compile_fog

            // We only target the HoloLens (and the Unity editor), so take advantage of shader model 5.
            #pragma target 5.0
            #pragma only_renderers d3d11

            #pragma shader_feature _USECOLOR_ON
            #pragma shader_feature _USEMAINTEX_ON
            #pragma shader_feature _USEEMISSIONTEX_ON
            #pragma multi_compile  __ _NEAR_PLANE_FADE_ON

            #include "HoloToolkitCommon.cginc"
            #include "VertexLitConfigurable.cginc"

            ENDCG
        }
    }
}