Calling (Admin)InitiateAuthRequest in the AWS Cognito To Get an Access Token with Scopes

I need to expose an api, which also allows us to get the scope, but I'm failing with all my attempts using aws cognito.

So I was hoping to do the following:

1. assign scope:foo to existing users and new users
2. get an access token back containing that scope of foo (using c# back end code)

Part I: Getting Access Token with Scope

So for getting a token it's the following:

var provider = new AmazonCognitoIdentityProviderClient(new BasicAWSCredentials(AccessKey, SecretKey));
var request1 = new AdminInitiateAuthRequest
            {
                UserPoolId = userPoolId,
                ClientId = request.ClientId,
                AuthFlow = AuthFlowType.ADMIN_NO_SRP_AUTH,
                AuthParameters =
                {
                    {"USERNAME", request.UserName},
                    {"PASSWORD", request.Password}
                }
            };
var response1 = await provider.InitiateAuthAsync(request);

Now, I can gain the tokens with this request/response (obviously with good credentials :) ). What I cannot figure out is how to ask for more scope items. Currently it only returns aws.cognito.signin.user.admin

Part II: User Attributes

With that said, I've also added a custom:some-attribute attribute. I can see it within UI for the General settings \ Attributes screen. I don't have any lambda triggers setup, BTW.

I'm finding that I can update the user settings, as I get an OK|200 status returned, but if I try and get the user, his updated attribute doesn't show up.

var request2 = new AdminUpdateUserAttributesRequest
            {
                UserAttributes = new List<AttributeType>
                    {
                       new AttributeType {
                           Name="custom:some-attribute",
                           Value=Guid.NewGuid().ToString("N")
                    };
                UserPoolId = userPoolId,
                Username = userName
            };

var response2 = await provider.AdminUpdateUserAttributesAsync(request);

Later I go to look up the user:

var result = await _provider.GetUserAsync(new GetUserRequest
        {
            AccessToken = response1.AuthenticationResult.AccessToken
        });

... my newly updated variable doesn't show in the result.UserAttribues AttributeType list.

Maybe I'm doing this wrong, but I cannot figure out how to create a scope (which I was thinking I could do an alternative via the custom attribute) and get the scope.

Equally, I cannot figure out how to pass in a scope when authenticating for tokens.

Thanks, Kelly