Use a bower override to pull in all the Bootstrap SCSS files individually (and JS). You can use Bootstrap’s own import order as a model and just omit the elements you don’t want. You’ll need to add the JS to the overrides too. Sage 8.4.2 shipped with some overrides so its
bower.json is a good example (just note the different package names—stick with
bootstrap rather than
bootstrap-sass unless you plan to use the other package).
For the JS you can probably get away with just using the single file specified in the Bootstrap
main property. If you want to split those up then include them in this order: