No, you can't enrol a student with any other enrolment mode other than a single registration when enrolling a student through the applicant section.
If a student is dual registered, you would enrol them through the applicant page as single registration and then make the amendment in their profile. This article explains Adding, enrolling applicants and sending communications to Applicants.
To change a student enrolment mode you would need to go to the Enrolment section of the student's profile.
Under enrolment mode, Click on the current enrolment mode and click Edit. Change the enrolment mode, change the date range if needed, then click Save Changes.