We do not have sales insight which may affect the answer? I need to know which date field is used by Marketo to capture the last lead activity such as form submission, click, web visit, etc.
I see a few different fields that could be the answer, and maybe the answer is more than one. Here are the tokenized examples I can see.
lead.SFDC Updated Date
Jonathan Ward - Would recommend to move this question to Products section.
For the Dates - No, Marketo doesn't has a Date Field to record dates which are specific to each type of activity - the only place you can track it is in the activity log. The tokens are to append the values into a Field - which can be a custom field. E.g. if you want to track the Date of a Most Recent Activity - you need a Date Field for that activity created, and setup a logic to update that Field by dynamically populating system's date using System Token.
Hope this helps!