Lets clarify some Facebook terminology.
A profile is a place on Facebook where you can share information about yourself, such as your interests, photos, videos, current city and hometown. To see your profile, click or tap your name or profile picture at the top of Facebook.
You must have a profile to create a Page or help manage one. Pages are places on Facebook where artists, public figures, businesses, brands, organizations and nonprofits can connect with their fans or customers. When someone likes or follows a Page on Facebook, they can start seeing updates from that Page in their News Feed.
To see an example of a Page, see the screenshot below.
You must have a profile to create a group or help manage one. Groups are a place to communicate about shared interests with certain people. You can create a group for anything — your family reunion, your after-work sports team, your book club — and customize the group’s privacy settings depending on who you want to be able to join and see the group. When you join a group on Facebook, you starting seeing content from that group in your News Feed.
To answer your specific questions:
Your business page will always be tied to a personal profile. (The public does not know which person profile is tied to the page.)
You MUST use your real name on your personal profile or Facebook will ban you. However, you can set your profile to private so no one can see anything.
There are no limit to the number of Facebook Pages you can open. So long as they are legit pages you can open as many as you need.
To run ads for your business you should sign up for https://business.facebook.com
Check out Facebook Blueprint to learn how to properly use Facebook Business to run ads.