4👍
People doesn’t approve jQuery + Vue for the simple reason that jQuery is not necessary and duplicates a lot of Vue functionality being less reactive, but jQuery CAN coexist with Vue.
If you start a new project I would recommend using another alternative (Bulma, Bootstrap vue, etc) that is more agnostic and does not depend on any other library.
In your case, I understand that only CSS classes have been customized. I think you could install the latest version of Bootstrap-vue and add those customizations, if the bootstrap version is the same, it should not collide too much. Still, I understand that it will be complicated, since Bootstrap-vue generates the HTML from its already created components, which makes it a bit complicated that the first one looks the way you want without adjusting.