iPhone to iPod back up

Yes, you can. It doesn't matter what generation the iPod touch is as long as it can run an iOS version equal to or greater than the version the iPhone 5 backup was made on.

Note:

Data that won't transfer from one kind of device to another

When you restore a device from a backup of another kind of device, like using an iPad backup for an iPhone, certain types of data won't transfer:

• Photos
• Messages and attachments in Messages
• Voice Memos
• Apps that aren't compatible with the device you’re setting up (For example, apps compatible only with iPad won't be transferred to your iPhone.)

About backups in iCloud and iTunes - Apple Support

Yes, photos will only be restored to the same type of device..

You can likely recovery the photos form the iTunes backup by:

Dr Phone for iOS Recovery - PC only

All-around Data Rescue Tool for Apple iPod