Two related questions:
It seems that Outlook.com "People" has mingled my Google contacts and my Facebook contacts. Can I separate them?
If I delete contacts in Google will they be automatically deleted from "People" in Outlook.com?
1. Yes, you can separate your Google contacts from your Facebook contacts.
Click on the little arrow next to the Outlook mail icon and select "People". From the "People" tab click on the little arrow next to "Manage" and from the popup menu that appears select "Manage Groups". A new frame will appear. Click on the + sign next to the word "Group" to add a new group. Add two new groups, one for Google Contacts and one for Facebook, and don't forget to type a name for each group that you add.
Go to Gmail and click on the little arrow next to the red word "Gmail", and select "Contacts". On the contacts page put a check mark next to all the contacts that you want to export. Click on the little arrow next to the word "More" and from the popup menu that appears select "Export". A new frame will pop up. Select the options "Selected contacts" and "Outlook CSV format (for importing into Outlook or another application)". Export your contacts to a convenient place where you can easily find them.
Now in Outlook from the Outlook "People" tab click on the little arrow next to the word "All" and select your new Google group. From the Google group select "Import from file" and import your Google contacts from the new contacts file you just downloaded from Gmail. The contacts should import properly to Outlook without requiring any additional editing.
The procedure for adding your Facebook contacts to Outlook is similar.
2. Since your are adding your contacts to Outlook from locally stored csv files, you can do whatever your want to your contact data on Google and Facebook, and it won't change a thing in Outlook.