OK - that's a lot of stuff to reply to. I think you're overthinking/analyzing and maybe further confusing yourself.
Btw, I'm near downtown LA and also use Spectrum. Don't be worried about RMS being located in the UK - all this stuff works the same anywhere in the world.
I think you would benefit greatly by checking the Introductory RW Videos made by RMS:
Particularly this one on publishing:
I think this will answer a lot of your questions. If you have further questions after you've watched the video(s), perhaps we can take it from there?
There are many 3rd party FTP apps out there for Mac, including Transmit, Forklift, Yummy FTP, Fetch, etc. They all will work, and people have their favorites.
RW has it's own publishing engine as well which you will learn about in the video.
You don't 'need' a hosting company to publish. You need a hosting account to publish your files to.
There are several methods you can use:
1. RW's own publishing tool
2. A third party FTP app
3. or usually you can publish from your hosting account's file manager which i think is usually located in C-Panel.
For the second two options you have to export your project locally and then upload the files to your hosting account.
OK - please watch the video!!