I'd say prioritize OAT over English. Not sure how true this statement is anymore but I don't believe you need to have finished ALL of your pre-reqs before interviewing (can always verify with specific schools); and of course science pre-reqs should be mostly done and graded before interviewing - English not so important. OAT scores are probably second or third behind GPA (being first) and optometry experience (being second or third I'd judge). After that gets you an invite, the interview weight can vary depending on the school. These are just my opinions.
You'll probably do fine on OAT easily with just 1-2 weeks of practice exams (and maybe a refresher in orgo). Biochem major proved very valuable to my OAT and optometry school experience and I really didn't have to work as hard as others.