You can do this with a smart list.
1) Filled Short Form
2) Clicked Link
3) Filled Long Form
The results will be all of the people who took all three actions.
Will this still work if I'm not using Marketo forms?
When add the "Filled out Form" filter to my smart list, I'm not able to choose out form because we are using gravity forms with a WordPress plugin.
Depends on how the server-side plugin actually posts the data.
If they use a form post, you will get a Fills Out Form activity.
If they use a REST or SOAP API, you will not get such an activity, and you also are highly vulnerable to an instance-wide DoS against all your integrations. They should not be doing this and I would yell at them if they are.
Neither of the above is following best practices for third-party forms, which should be using a hidden form submit on the client side.
I got this to work!
I just had to drag over my form field that we created as a filter. Thanks for the help and advice!