Yeah, you really don't need the bootstrap and lodash in most cases! Especially not when you do all your css work yourself and use VueJS components for your frontend. Of course you can strip them all out. That's what I do most of the time as well ;)
jQuery is nice to have when you use everything regarding the bootstrap framework like alerts, modals, menu, tabs etc. This way you don't have to figure out yourself how to include everything.
Regarding lodash. It's just like collections that awesome helpers for arrays. Lodash make it easier for you to sort arrays, group things, loop over them etc. It has a lot of helpers methods like the collections in laravel but then for javascript. If you don't use it I would recommend you to remove it in general, because it's pretty big and can make things slower on the long term.
Let me know you have more questions ;)