Leads Converting to Deals Issue

Leads Converting to Deals Issue

Hello,
I am trying to have my leads convert to deals. In leads, I have the contact look up required, so I do not need any name field in leads. However it says last name is a field that cannot even be modified, the settings dots are greyed out and cannot even be clicked. How can I delete the "last name" field in Leads? 
When I click convert to deal, it creates a new contact based on the last name field, instead of the contact look up field.
To try and get around this, I created a custom module, but I cannot figure out to to convert the custom module to a Deal.

Somebody please help!