Did you ever resolve this? I've just completed a v7 upgrade and have the same issue. I tried changing the property type to Umbraco.TrueFalse but still it just displays as Umbraco.NoEdit with no ability to unlock a member.

Whilst this isn't ideal it does seem to do the job for the moment. What I have done is hook into the EditorModelEventManager.SendingMemberModel event and change the view from readonlyvalue to boolean as follows:

private void EditorModelEventManager_SendingMemberModel(System.Web.Http.Filters.HttpActionExecutedContext sender, EditorModelEventArgs<global::Umbraco.Web.Models.ContentEditing.MemberDisplay> e)
{
    var currentUsersGroups = e.UmbracoContext.Security.CurrentUser.Groups.ToList();
    var isMembershipAdmin = currentUsersGroups.Exists(x =>
        x.Alias.Equals("membershipAdministrator", StringComparison.OrdinalIgnoreCase));

    foreach (var p in e.Model.Properties)
    {
        if (p.Alias.Equals("umbracoMemberLockedOut") && isMembershipAdmin)
        {
            p.View = "boolean";
        }
    }
}

To provide some further context, the reason this appears to be necessary is because the core is forcing the view to be readonlyvalue in the MemberModelMapper class:

https://github.com/umbraco/Umbraco-CMS/blob/7447cc4b7eb2c66f2ba4ecba02d0dbdfbbab2d4f/src/Umbraco.Web/Models/Mapping/MemberModelMapper.cs#L281

{
    //it's a generic provider so update the locked out property based on our known constant alias
    var isLockedOutProperty = result.SelectMany(x => x.Properties).FirstOrDefault(x => x.Alias == Constants.Conventions.Member.IsLockedOut);
    if (isLockedOutProperty?.Value != null && isLockedOutProperty.Value.ToString() != "1")
    {
        isLockedOutProperty.View = "readonlyvalue";
        isLockedOutProperty.Value = _localizedTextService.Localize("general/no");
    }
}
else
{
    var umbracoProvider = (IUmbracoMemberTypeMembershipProvider)provider;

    //This is kind of a hack because a developer is supposed to be allowed to set their property editor - would have been much easier
    // if we just had all of the membeship provider fields on the member table :(
    // TODO: But is there a way to map the IMember.IsLockedOut to the property ? i dunno.
    var isLockedOutProperty = result.SelectMany(x => x.Properties).FirstOrDefault(x => x.Alias == umbracoProvider.LockPropertyTypeAlias);
    if (isLockedOutProperty?.Value != null && isLockedOutProperty.Value.ToString() != "1")
    {
        isLockedOutProperty.View = "readonlyvalue";
        isLockedOutProperty.Value = _localizedTextService.Localize("general/no");
    }
}

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