I need some guidance with regard to page_theme.php and assets in C58.4

Here are a few references that we have used to get a mind-meld with this thing, we have a lot more, but these should suffice for this discussion.
Referrence1:https://documentation.concrete5.org/developers/pages-themes/designin...
Referrence2: "Clonemental Theme" page_theme.php (using it as a template to impiment in a new theme we are concretalizing)

We think we understand the difference between requiring and providing assets, if I am correct, essentially:
a) providing assets means my theme will provide the asset (for the frontend???) ex: bootstrap, js etc.,
b) requiring assets means I want C5 to provide the BS, JS etc. (for the backend???).

In Andrew's screen cast (referrence1) there is a piece of code as follows:

public function registerAssets()
{
line1 $this->providesAsset('javascript', 'bootstrap/*');
line2 $this->providesAsset('css', 'bootstrap/*');
line3 $this->providesAsset('css', 'blocks/form');
line4 $this->providesAsset('css', 'core/frontend/*');
line5 $this->requireAsset('javascript', 'jquery');
}

I get what the objective is, my question is:
If I am (via theme) providing the assets, what is the purpose of Line5? My theme requires jquery, so how do I allow both to be in use - or nuke one of them, see SUMMARY below...

In Referrence2, there is this piece of code:
public function registerAssets()
{
//$this->providesAsset('javascript', 'bootstrap/*');
$this->providesAsset('css', 'bootstrap/*');
$this->providesAsset('css', 'blocks/form');
$this->providesAsset('css', 'blocks/social_links');
$this->providesAsset('css', 'blocks/share_this_page');
$this->providesAsset('css', 'blocks/feature');
$this->providesAsset('css', 'blocks/testimonial');
$this->providesAsset('css', 'blocks/date_navigation');
$this->providesAsset('css', 'blocks/topic_list');
$this->providesAsset('css', 'blocks/faq');
$this->providesAsset('css', 'blocks/tags');
$this->providesAsset('css', 'core/frontend/*');
$this->providesAsset('css', 'blocks/feature/templates/hover_description');

$this->providesAsset('css', 'blocks/event_list');

$this->requireAsset('css', 'font-awesome');
$this->requireAsset('javascript', 'jquery');
$this->requireAsset('javascript', 'picturefill');
$this->requireAsset('javascript-conditional', 'html5-shiv');
$this->requireAsset('javascript-conditional', 'respond');
}
SUMMARY:
========
Of course, there are some items above that I don't need (I beleive), so here are my questions:

1) If I wanted to "provide" access to my own "CSS", how would I do this?
2) Why would one not GROUP (if this can be done) Require and Provide Separately?
3) Is the order of provide/require important,
4) Last, my theme provides jquery and C5 provides jquery I get (I believe) collisions, which is what I want to avoid.
If I remove jquery (as Andrew did in his screencast) my theme fails, but the backend seems to work.
If I put my theme's jquery back in (along with C5 jquery) everything grinds to a halt when I add a Content Block (for example),
-->> Here is my question (loaded of course) what do I do to prevent this?

I know it's a lot of info and so as not to waste everyone's time, we have spent a week going over everything we can find.
We are really trying to get our heads around this and many of the Links and Docs for C5 are either broken or refer to previous versions.

Thanks for any insight and guidance.