We're working on a project which we will need to submit to this group to get the site 'certified'. Since we will be discussing this project -- which will be 2.5 and Bootstrap by the way -- we could profit from that project's feedback.
Wouldn't it be amazing if the standard templates would all be at least 'largely' accessible and we would indicate the 'offences' for people to avoid if they want to have an accessible version .
Their checklist is available in Dutch en French, but you can get a basic idea of their approach on
this webpage.
Their guidelines are a 'minimal' approach, they are working on a stricter approach which includes things like clarity of language, etc -- so probably out of scope for a CMS.