Problem updating an existing Salesforce record

I have landing pages built in Leadpages for these purposes:

• Retrieving a lead magnet, and the form only asks for first name, last name and email. Zapier creates a Salesforce lead without a problem. I’m the owner of this record. 
• Requesting a demo. The form asks for first, last, email, title, company and phone number. Zapier creates a Salesforce lead without a problem. Someone else owns this record when it’s created.
• Requesting a demo AFTER you’ve downloaded a lead magnet - I want to update the record with the new information and change the owner. This is the one that doesn’t work. 

The problem I can’t seem to solve is updating an existing record with additional information, and changing the owner. Here’s what I’m doing (and that isn’t working); 

1. Trigger is the new form submission in Leadpages. This works fine.
2. Find Record in Salesforce 
   • Action Event = Find Record
   • Account is mine
   • Set up action:
     • Salesforce Object is LEAD
     • Field to Search by is EMAIL (because that’s how we’re finding the record)
     • Search Value is Email: [selected the email address from the new form submission]
     • Should this step be a success… - I’ve tried this both ways and it doesn’t make a difference (I know it DOES matter, in general, but I’m just trying to update an existing record) 
     • Create Salesforce Record if it doesn't exist yet  - I’ve tried this enabled and disabled, and it doesn't make a difference (I know it DOES matter, in general, but I’m just trying to update an existing record)
3. Update Record in Salesforce - In the previous step, it should have found the record.
   • Salesforce Object = Lead
   • Record to update = the lead with the email address that I found in step #2 
   • For updating the record itself, I match up first name, last name, record type, title, organization, phone, email and a few other things.

BUT, it’s just not updating the record -- the record still only has first name, last name and email from the original form. 

I’m sure this is something obvious, so thanks in advance for your patience and help.