[SalesForce] How to override standard button on standard objects like Contact with a Flow

What if instead of redirecting to a custom VF page that uses apex:detail, you redirect to a URL that suppressed the VF override and shows the default view page?

That's what I did for my case object: My new/view/edit buttons all redirect to a 'Redirect' VF page that does nothing but call an extension method that determines whether to show a VF page or suppress the VF override.

Here is the 'redirect' vf page:

<apex:page standardController="Case" extensions="CaseUniversalControllerExtension" action="{!pageRedirect}">
</apex:page>

The pageRedirect() method that VF page is referencing has the following bits of relevant code:

    map<string, string> pageParameters = ApexPages.currentPage().getParameters();
  //uses info from SF URL to determine which button was clicked
    if(pageParameters.get('Id') == null) detectedMode = 'New';
    else if(pageParameters.get('Id') != null && pageParameters.get('retURL') != null) detectedMode = 'Edit';
    else if(pageParameters.get('Id') != null && pageParameters.get('retURL') == null) detectedMode = 'View';

With the 'mode' determined (view/new/edit), you can determine which VF page you want to redirect to, or you can choose to suppress the VF page and show the default:

here is redirecting to another VF page:

        if(detectedMode == 'New') return new PageReference('/apex/CasePortalUserEdit');
        else if(detectedMode == 'Edit') return new PageReference('/apex/CasePortalUserEdit?id='+pageParameters.get('Id') + '&retURL=/' + pageParameters.get('Id'));
        else if(detectedMode == 'View') return new PageReference('/apex/CasePortalUserView?id='+pageParameters.get('Id') + '&retURL=/' + pageParameters.get('Id'));     

and here is suppressing the VF page:

        if(detectedMode == 'New') return new PageReference('/500/e?ent=Case&nooverride=1&RecordType='+recordTypeID+'&retURL=/500/o');
        else if(detectedMode == 'Edit') return new PageReference('/' + pageParameters.get('Id') + '/e?nooverride=1&RecordType='+recordTypeID+'&retURL=/' + pageParameters.get('Id'));
        else if(detectedMode == 'View') return new PageReference('/' +pageParameters.get('Id') + '?nooverride=1');     

the key parameter for suppressing a VF page is NoOverride=1

As far as I know, your best bet here is still to use Visualforce and just surface lightning through that page.

<apex:page standardController="ChildObject__c" recordSetVar="children">
    <!-- include lightning here -->
</apex:page>