Surface shader vertex function 'SplatmapVert' not found

I am trying to combine two working shaders into one new one but i get the error as seen in title. I am not sure why SplatmapVert is acceptable in the terrain shader i am taking it from but cannot be found when used in the combined shader. Here is the line i want to copy over: #pragma surface surf Lambert vertex:SplatmapVert finalcolor:SplatmapFinalColor finalprepass:SplatmapFinalPrepass finalgbuffer:SplatmapFinalGBuffer noinstancing

Is it as simple as missing some reference somewhere? I am new to shaders so i worry it may be.

See below for (1)the terrain shader, (2)the FOW shader and (3)my attempt at combining them.

The terrain shader (with the pragma line i want):

 Shader "Nature/Terrain/Diffuse" {
     Properties {
         [HideInInspector] _Control ("Control (RGBA)", 2D) = "red" {}
         [HideInInspector] _Splat3 ("Layer 3 (A)", 2D) = "white" {}
         [HideInInspector] _Splat2 ("Layer 2 (B)", 2D) = "white" {}
         [HideInInspector] _Splat1 ("Layer 1 (G)", 2D) = "white" {}
         [HideInInspector] _Splat0 ("Layer 0 (R)", 2D) = "white" {}
         [HideInInspector] _Normal3 ("Normal 3 (A)", 2D) = "bump" {}
         [HideInInspector] _Normal2 ("Normal 2 (B)", 2D) = "bump" {}
         [HideInInspector] _Normal1 ("Normal 1 (G)", 2D) = "bump" {}
         [HideInInspector] _Normal0 ("Normal 0 (R)", 2D) = "bump" {}
         // used in fallback on old cards & base map
         [HideInInspector] _MainTex ("BaseMap (RGB)", 2D) = "white" {}
         [HideInInspector] _Color ("Main Color", Color) = (1,1,1,1)
     }
 
     CGINCLUDE
         #pragma surface surf Lambert vertex:SplatmapVert finalcolor:SplatmapFinalColor finalprepass:SplatmapFinalPrepass finalgbuffer:SplatmapFinalGBuffer noinstancing
         #pragma multi_compile_fog
         #include "TerrainSplatmapCommon.cginc"
 
         void surf(Input IN, inout SurfaceOutput o)
         {
             half4 splat_control;
             half weight;
             fixed4 mixedDiffuse;
             SplatmapMix(IN, splat_control, weight, mixedDiffuse, o.Normal);
             o.Albedo = mixedDiffuse.rgb;
             o.Alpha = weight;
         }
     ENDCG
 
     Category {
         Tags {
             "Queue" = "Geometry-99"
             "RenderType" = "Opaque"
         }
         // TODO: Seems like "#pragma target 3.0 _TERRAIN_NORMAL_MAP" can't fallback correctly on less capable devices?
         // Use two sub-shaders to simulate different features for different targets and still fallback correctly.
         SubShader { // for sm3.0+ targets
             CGPROGRAM
                 #pragma target 3.0
                 #pragma multi_compile __ _TERRAIN_NORMAL_MAP
             ENDCG
         }
         SubShader { // for sm2.0 targets
             CGPROGRAM
             ENDCG
         }
     }
 
     Dependency "AddPassShader" = "Hidden/TerrainEngine/Splatmap/Diffuse-AddPass"
     Dependency "BaseMapShader" = "Diffuse"
     Dependency "Details0"      = "Hidden/TerrainEngine/Details/Vertexlit"
     Dependency "Details1"      = "Hidden/TerrainEngine/Details/WavingDoublePass"
     Dependency "Details2"      = "Hidden/TerrainEngine/Details/BillboardWavingDoublePass"
     Dependency "Tree0"         = "Hidden/TerrainEngine/BillboardTree"
 
     Fallback "Diffuse"
 }

The Fog of War shader i am trying to combine with it:

 Shader "Fog Of War/Terrain" {
     Properties {
         _MainTex ("Base (RGB)", 2D) = "white" {}
     }
     SubShader {
         Tags { "RenderType"="Opaque" }
         LOD 200
         
         CGPROGRAM
         #pragma surface surf Lambert
         #include "FOWIncludes.cginc"
 
         sampler2D _MainTex;
         sampler2D _FOWTex;
         float4 _FOWTex_ST;
 
         struct Input {
             float2 uv_MainTex;
             float3 worldPos;
         };
 
         void surf (Input IN, inout SurfaceOutput o) {
             half4 c = tex2D(_MainTex, IN.uv_MainTex);
             half4 fow = tex2D(_FOWTex, TRANSFORM_TEX(IN.worldPos.xz, _FOWTex));
             half4 t = TransformColourFOWAO(c, fow);
             o.Albedo = t.rgb;
             o.Alpha = t.a;
         }
         ENDCG
     } 
     FallBack "Diffuse"
 }

   

The combined result so far (should be the same effect as the FOW one above):

     Shader "Nature/Terrain/FOW" 
     {
         Properties 
         {
             [HideInInspector] _Control ("Control (RGBA)", 2D) = "red" {}
             [HideInInspector] _Splat3 ("Layer 3 (A)", 2D) = "white" {}
             [HideInInspector] _Splat2 ("Layer 2 (B)", 2D) = "white" {}
             [HideInInspector] _Splat1 ("Layer 1 (G)", 2D) = "white" {}
             [HideInInspector] _Splat0 ("Layer 0 (R)", 2D) = "white" {}
             [HideInInspector] _Normal3 ("Normal 3 (A)", 2D) = "bump" {}
             [HideInInspector] _Normal2 ("Normal 2 (B)", 2D) = "bump" {}
             [HideInInspector] _Normal1 ("Normal 1 (G)", 2D) = "bump" {}
             [HideInInspector] _Normal0 ("Normal 0 (R)", 2D) = "bump" {}
             [HideInInspector] _MainTex ("BaseMap (RGB)", 2D) = "white" {}
             [HideInInspector] _Color ("Main Color", Color) = (1,1,1,1)
         }
         
             //CGINCLUDE
             //#pragma vertex:SplatmapVert finalcolor:SplatmapFinalColor
             //ENDCG
     
             SubShader 
             {
                 Tags 
                 {  
                     "RenderType"="Opaque" 
                 }
                 LOD 200
             
                 CGPROGRAM
                 #pragma multi_compile_fog
                    #pragma surface surf Lambert //vertex:SplatmapVert finalcolor:SplatmapFinalColor finalprepass:SplatmapFinalPrepass finalgbuffer:SplatmapFinalGBuffer noinstancing
                 #include "FOWIncludes.cginc"
     
                 sampler2D _MainTex;
                 sampler2D _FOWTex;
                 float4 _FOWTex_ST;
     
                 struct Input 
                 {
                     float2 uv_MainTex;
                     float3 worldPos;
                 };
     
     
                 void surf (Input IN, inout SurfaceOutput o) 
                 {
                     half4 splat_control;
                     half weight;
                     fixed4 mixedDiffuse;
     
                     //SplatmapMix(IN, splat_control, weight, mixedDiffuse, o.Normal);
     
                     half4 c = tex2D(_MainTex, IN.uv_MainTex);
                     half4 fow = tex2D(_FOWTex, TRANSFORM_TEX(IN.worldPos.xz, _FOWTex));
                     half4 t = TransformColourFOWAO(c, fow);
     
     
                     o.Albedo = t.rgb;
                     o.Alpha = t.a;
                 }
                 ENDCG
     
     
     
             } 
     
         Dependency "AddPassShader" = "Hidden/TerrainEngine/Splatmap/Diffuse-AddPass"
         Dependency "BaseMapShader" = "Diffuse"
         Dependency "Details0"      = "Hidden/TerrainEngine/Details/Vertexlit"
         Dependency "Details1"      = "Hidden/TerrainEngine/Details/WavingDoublePass"
         Dependency "Details2"      = "Hidden/TerrainEngine/Details/BillboardWavingDoublePass"
         Dependency "Tree0"         = "Hidden/TerrainEngine/BillboardTree"
     
         Fallback "Diffuse"
     
     }