Questions about serving a Vue Component Library as an NPM package - vue.js

Question

Gist for my vite and tsconfigs is here.
Disclaimer: Very new to how packages and modules work. I'm a yung'un who never had to think beyond import/export. So I may have used the term "tree-shaking" too many times below.
I'm looking to move some re-used Vue components from old projects into a shared private package that I can consume through npm. I do not intend to consume it via CDN, only Vite projects. Here is the directory structure of the "package" I've come up with:
my_components
| package.json
│ vite.config.ts
│ tsconfig.json
| tsconfig.vite.json
│
└───src
│ │ index.ts
│ │
│ └───components
│ | index.ts
│ | MyButton.vue
│ | MyDropdown.vue
| | ...
| |
| └───assets
| |
| └───sass
| |
| | style.scss
| | ...
│
└───dist
│ my-lib.es.js
│ style.css
└───types
| index.d.ts
| src/MyButton.vue.d.ts
| src/MyDropdown.vue.d.ts
I am using Vite in library mode and generating es module + bundled.
The resulting build is around 1MB of CSS and 300kb of JavaScript (before gzip). The reason for this is that there a lot of one-off components that may or may not be used in the consuming project but still bring in their own unique dependencies (fullcalendar, prismjs, tiny mce, etc.). The ideal scenario is that my shared package can have a tonne of dependencies while my consuming project still only includes what it uses in its own build.
I have a few questions and doubts and gaps in knowledge about the whole process:
A. How do I make the sass variables be able to be overridden?
This is an important requirement since styling the components uniquely per project would be impossible otherwise (?).
It seems the only way to do this would be to add src/assets/sass/style.scss as an export in my package.json file. The consumer of this package would then include this file instead of the bundled/minified dist/style.css and build it themselves. This is how Bootstrap's npm package does it.
B. How do dependencies and tree-shaking work for libraries distributed like this? How is the build process changing my existing code?
B.1) I only used import/export throughout my code. Is the resulting bundled file dist/my-lib.es.js one huge module, or does it somehow manage to preserve multiple module definitions inside a single file?
This project depends on bootstrap, prismjs, quill, fullcalendar, etc. The list goes on. All of these are in my devDependencies.
B.2) Can I expect the full source of these dependencies to have been included in my bundle, or are these "tree-shaken" by Vite when building my package dist?
B.3) When I import this bundled JS inside my consuming project, is it "tree-shakeable"? If not, how do I make it so? I want to minimize what is built in the final project app to only what is used from my shared package.
C. Is there a way to distribute without building anything at all?
Since this package is only meant to be consumed by other (Vite) projects, is there a way to package everything without building a dist folder at all? In this scenario, I would publish my src folder only and the consuming project would be expected to include/import/build what they require. This should definitely minimize what goes into the final project build, right!?
C.1) If this is possible (and I haven't found any online sources about this), how would I set-up Typescript, ESLint and Vite in the consuming project to properly process the raw code?
P.S. I want it setup as a package instead of a git repository because I might delegate the shared package development to someone else later on, and an npm package is a simpler thing to consume than a git sub-repository IMO. Feel free to point out why I may be wrong in this, but please do not do so as the main solution in your answer.
D. Analyzing everything!
I imagine I would have a better grasp of the above concepts if I could analyze what is being included in builds on both levels (shared package build, and consuming project's application build). However, I currently know of no ways or tools or workflows to analyze such things (owing to my inexperience). Recommendations?