Unlock carrier and backup questions

I have a 6+ that is an ATT device. I have successfully requested and been granted an unlock from their network. They provided me with two possible scenaria.

Use a SIM from another carrier: Using a Non-AT&T SIM Card:

1. Remove your SIM card and insert the new SIM card.

2. Complete the setup process.

---OR---

Using an AT&T SIM Card:

1. Back up your iPhone.

2. When you have a backup, erase your iPhone.

3. Restore your iPhone from the backup you just made.

I am not quite ready to "jump ship" yet, but when I do pull the trigger, I need to know EXACTLY what information on my phone I will lose.

Assumptions: I use the IOS email, contacts, notes, and calendar apps with my GMAIL account information and data.

As you can see, they want me to backup and then "erase" my phone. This has me worried. I've nto done this before.

So I guess I'll start with questions, and then ask if it is all contained in my iTunes backup to computer.

1. Purchased apps and the specific app settings within the apps.
2. Pictures/videos
3. Non-camera roll albums
4. Music library
5. Notes
6. Google voice app settings and historical messages
7. iMessage texts (historical messages)
8. Any of my google related email/contacts/calendar info mentioned above.
9. Voicemails
10. Recent call history
11. Map destination history

Anything else may I have forgotten?

Thanks in advance for any information you can provide.