Form 7004 is only for the types of returns listed. Form 5472 is only for corporations. Corporations cannot be disregarded entities. So, it does not seem like either 5472 or 7004 applies. If you are filing a form 1040 or a form 1040NR with an attached schedule C to report your sole-member LLC activity, then you should file a form 4868 or a form 2350 depending on your circumstances to file for an extension of time to file your return.