An online teacher could speak to your academics and communication skills, but if you look at the form that is emailed to the teachers to fill out, they also need to rate you as a student in how you perform with class group work. It has questions asking about how you do with taking leadership, and how well of a follower you are as well. I imagine that rating scale that the teachers do has some impact on your WCS, so I'd call admissions when you start your application to ask about online courses.
If you won't have a classroom English class next year, then maybe they'll let one of your other teachers do it that know you at a more personal level; the same way they allow home-schooled applicants to give those recommendation slots to coaches and other adults.
PS to look at the form they email teachers, on the application you can click the right buttons on that part of it to lead you to a hard-copy of the form if you had a teacher that preferred to fax their recommendation.