I think you have a decent shot for those schools. However, you need to diversify your ECs a little bit. I think Yale might be a bit of a reach simply because of that fact-- while you have an admirable focus on latin, you’re a bit lacking in other fields. BUT, latin combined with biology is a very positive aspect of your application. Your SAT score will help you with Duke and Williams, but not necessarily with Yale. If they’ve already accepted students from your school in the past, then they don’t need it necessarily to see if you’re a good fit. Duke, I’d say is a slight reach. Yale is a reach but it seems favorable because of your dedication to Latin (though it might turn out to be counterproductive in the end) but I’d say Williams is very possible.