how to add a custom claim to a web token? b2c custom policys - azure-ad-b2c-custom-policy

Question

I have a custom policy on Azure B2C.
When the user signs up, I need to remove the display for "DisplayName" (text box) from the signup screen. Instead, I need to copy the email into DisplayName and add the DisplayName to the web token.
I have succesfully completed the first part, I no longer ask the user for the displayName, but I am not getting DisplayName in the token, so I can't know if I am copying it right.
I tried to copy and modify given_name, as that one works, but apparently something went wrong along the lines.
How do I achieve that? or what I am missing?
My custom policy:
<RelyingParty>
<DefaultUserJourney ReferenceId="SignUpOrSignIn" />
<TechnicalProfile Id="PolicyProfile">
<DisplayName>PolicyProfile</DisplayName>
<Protocol Name="OpenIdConnect" />
<OutputClaims>
<OutputClaim ClaimTypeReferenceId="displayName"/>
<OutputClaim ClaimTypeReferenceId="givenName" />
<OutputClaim ClaimTypeReferenceId="surname" />
<OutputClaim ClaimTypeReferenceId="email" />
<OutputClaim ClaimTypeReferenceId="objectId" PartnerClaimType="sub"/>
<OutputClaim ClaimTypeReferenceId="identityProvider" />
<OutputClaim ClaimTypeReferenceId="tenantId" AlwaysUseDefaultValue="true" DefaultValue="{Policy:TenantObjectId}" />
</OutputClaims>
<SubjectNamingInfo ClaimType="sub" />
</TechnicalProfile>
</RelyingParty>
Base file:
<ClaimType Id="displayName">
<DisplayName>Display Name</DisplayName>
<DataType>string</DataType>
<UserHelpText>Your display name.</UserHelpText>
</ClaimType>
...
<ClaimsTransformation Id="CopyEmailAddress" TransformationMethod="CopyClaim">
<InputClaims>
<InputClaim ClaimTypeReferenceId="email" TransformationClaimType="inputClaim"/>
</InputClaims>
<OutputClaims>
<OutputClaim ClaimTypeReferenceId="displayName" TransformationClaimType="outputClaim"/>
</OutputClaims>
</ClaimsTransformation>
...
<TechnicalProfiles>
<TechnicalProfile Id="login-NonInteractive">
<DisplayName>Local Account SignIn</DisplayName>
<Protocol Name="OpenIdConnect" />
<Metadata>
<Item Key="ProviderName">https://sts.windows.net/</Item>
<Item Key="METADATA">https://login.microsoftonline.com/{tenant}/.well-known/openid-configuration</Item>
<Item Key="authorization_endpoint">https://login.microsoftonline.com/{tenant}/oauth2/token</Item>
<Item Key="response_types">id_token</Item>
<Item Key="response_mode">query</Item>
<Item Key="scope">email openid</Item>
<!-- Policy Engine Clients -->
<Item Key="UsePolicyInRedirectUri">false</Item>
<Item Key="HttpBinding">POST</Item>
</Metadata>
<InputClaims>
<InputClaim ClaimTypeReferenceId="signInName" PartnerClaimType="username" Required="true" />
<InputClaim ClaimTypeReferenceId="password" Required="true" />
<InputClaim ClaimTypeReferenceId="grant_type" DefaultValue="password" AlwaysUseDefaultValue="true" />
<InputClaim ClaimTypeReferenceId="scope" DefaultValue="openid" AlwaysUseDefaultValue="true" />
<InputClaim ClaimTypeReferenceId="nca" PartnerClaimType="nca" DefaultValue="1" />
</InputClaims>
<OutputClaims>
<OutputClaim ClaimTypeReferenceId="objectId" PartnerClaimType="oid" />
<OutputClaim ClaimTypeReferenceId="tenantId" PartnerClaimType="tid" />
<OutputClaim ClaimTypeReferenceId="givenName" PartnerClaimType="given_name" />
<OutputClaim ClaimTypeReferenceId="surName" PartnerClaimType="family_name" />
<OutputClaim ClaimTypeReferenceId="displayName" PartnerClaimType="email" />
<OutputClaim ClaimTypeReferenceId="userPrincipalName" PartnerClaimType="upn" />
<OutputClaim ClaimTypeReferenceId="authenticationSource" DefaultValue="localAccountAuthentication" />
</OutputClaims>
</TechnicalProfile>
....

Answer 1

Try to use in your login-Noninteractive your displayName claim like this:
ClaimTypeReferenceId="email" PartnerClaimType="displayName"
You really don't need the claims transformation "CopyEmailAddress"