Combining two shaders into one

I know there is already questions about this, but I can't seem to get this woking. Combining the functions fails for me every time. Some insights are greatly appreciated!

its for a VR app.

Shader 1(maps texture to inside of cube):

Shader "Unlit/CubeMappy" { Properties { _MainTex("MainTex", 2D) = "black" {} _MainTex2("MainTex2", 2D) = "black" {}
_SecondTex ("SecondTexture", 2D) = "white" {} _DisolveTexture("Disolve Texture", 2D) = "white" {} _Blend("Blend Amount", Range(0,1)) = 1

     _Yaw ("Yaw", Float ) = 0
     [MaterialToggle] _Stereoscopic ("Stereoscopic", Float ) = 0
 }
 SubShader {
     Tags { "RenderType"="Opaque" }
     LOD 100
     Pass {
         Name "FORWARD"
         Cull Front
         ZWrite Off
         
         CGPROGRAM
         
         #pragma vertex vert        
         #pragma fragment frag    
          
         #include "UnityCG.cginc"

          struct appdata
           {
               float4 vertex : POSITION;
               float2 uv : TEXCOORD0;
           };
  
           struct v2f
           {
               float2 uv : TEXCOORD0;
               float2 uv2 : TEXCOORD1;
               float4 vertex : SV_POSITION;
           };            
         
         struct VertexInput {
             float4 vertex : POSITION;
         };

         struct VertexOutput {
             float4 pos : SV_POSITION;
             float4 posWorld : TEXCOORD0;
         };
                     
             uniform sampler2D _MainTex; uniform float4 _MainTex_ST;        
             
             sampler2D _MainTex2;
             sampler2D _SecondTex;
             float4 _MainTex2_ST;
             float4 _SecondTex_ST;
                          
         uniform float _Yaw;
         uniform fixed _Stereoscopic;

         VertexOutput vert (VertexInput v) {
             VertexOutput o = (VertexOutput)0;
             o.posWorld = mul(unity_ObjectToWorld, v.vertex); 
             o.pos = UnityObjectToClipPos(v.vertex); 
             return o;
         }
         
         //
         
         v2f vert (appdata v)
           {
               v2f o;
               o.vertex = UnityObjectToClipPos(v.vertex);
               o.uv = TRANSFORM_TEX(v.uv, _MainTex2);
               o.uv2 = TRANSFORM_TEX(v.uv, _SecondTex);
               return o;
           }
           
           half _Blend;
           sampler2D _DisolveTexture;
           fixed4 frag (v2f i) : SV_Target
           {
               fixed4 texture1 = tex2D(_MainTex2,i.uv); 
               fixed4 texture2 = tex2D(_SecondTex,i.uv); 
               return lerp(texture1,texture2,saturate(sign(_Blend-tex2D(_DisolveTexture,i.uv).r)));
           }
           
           //
           
           float2 CubemapUV(float3 dir, float yaw, float stereoscopic)
         {
             yaw += 0.5;
             float gC = (acos(dir.g) / 3.141592654);
             float2 N = float2((((atan2(dir.r, dir.b) / 6.28318530718) + 0.5) + yaw), frac(gC));
             N.y *= -1;
             float2 offset = stereoscopic ? float2(0.0, lerp(0.0, 0.5, unity_StereoEyeIndex)) : float2(0, 0);
             float2 M = frac((offset + lerp(N, (N*float2(1, 0.5)), stereoscopic)) );
             return M;
         }  

         float4 frag(VertexOutput i) : COLOR {
             return tex2D(_MainTex, CubemapUV( normalize(i.posWorld.rgb) , _Yaw, _Stereoscopic));
         }    
         ENDCG
     }
 }
 FallBack "Diffuse"

}

Shader 2(Dissolves between two textures):

Shader "Unlit/Dissolve2Tex" { Properties { _MainTex ("Texture", 2D) = "white" {} _SecondTex ("SecondTexture", 2D) = "white" {} _DisolveTexture("Disolve Texture", 2D) = "white" {} _Blend("Blend Amount", Range(0,1)) = 1 }

   SubShader
   {
       Tags { "RenderType"="Opaque" }
       LOD 100        

       Pass
       {            
           CGPROGRAM
           #pragma vertex vert
           #pragma fragment frag
  
           #include "UnityCG.cginc"
  
           struct appdata
           {
               float4 vertex : POSITION;
               float2 uv : TEXCOORD0;
           };
  
           struct v2f
           {
               float2 uv : TEXCOORD0;
               float2 uv2 : TEXCOORD1;
               float4 vertex : SV_POSITION;
           };
 
           sampler2D _MainTex;
           sampler2D _SecondTex;
           float4 _MainTex_ST;
           float4 _SecondTex_ST;
           v2f vert (appdata v)
           {
               v2f o;
               o.vertex = UnityObjectToClipPos(v.vertex);
               o.uv = TRANSFORM_TEX(v.uv, _MainTex);
               o.uv2=TRANSFORM_TEX(v.uv, _SecondTex);
               return o;
           }
 
           half _Blend;
           sampler2D _DisolveTexture;
           fixed4 frag (v2f i) : SV_Target
           {
               fixed4 texture1 = tex2D(_MainTex,i.uv); 
               fixed4 texture2 = tex2D(_SecondTex,i.uv); 
               return lerp(texture1,texture2,saturate(sign(_Blend-tex2D(_DisolveTexture,i.uv).r)));
           }
           ENDCG
       }
   }

}