What setup to use with in a famliy with 2 (or 3) Persons?
You need to understand that an Apple ID is not (or may not be) the same as an iCloud Account, which is not (or may not be) the same as an iTunes Store Account. An Apple ID is the credential set you use for accessing various services by Apple. Once you have an Apple ID, you can associate it with different services from Apple.

Anyone can create an Apple ID by visiting My Apple ID. Once you have an Apple ID (or more), you can choose how you would wish to use it.

For your case, you need three Apple IDs to keep things simple:


One Apple ID shared between all the members of your family for content purchases from the iTunes and App Stores
One individual Apple ID for your wife for iCloud, iMessage and FaceTime
One individual Apple ID for you for iCloud, iMessage and FaceTime


Here's how you would use these Apple IDs on the devices and PCs:


iTunes Store Purchases - In the case of a family (and specifically for you), you would have one Apple ID whose credentials are known by all family members so that all content purchased from the iTunes and App Stores can be shared across all devices.


You configure this on your iPhone, your wife's iPhone and your infant's iPod Touch under Settings > iTunes &amp; App Stores menu option.
You configure this in iTunes on your PC as well as on your wife's PC from the Store > Sign In... menu option.

iCloud Services - In almost every case, this would be an individual Apple ID so that Find My iPhone, Mail, Calendar, Reminders, etc., are segregated by user.


You configure your Apple ID on your iPhone under Settings > iCloud.
Your wife would configure her Apple ID on her iPhone under Settings > iCloud.
You do not configure this in iTunes on the PCs. However, if you use the iCloud Control Panel for Windows, you can configure it there.
You do not configure this for your infant at this point in time.

iMessage - In almost every case, this would be an individual Apple ID so that each person receives and manages messages intended for that person.


You configure your Apple ID on your iPhone under Settings > Messages.
Your wife would configure her Apple ID on her iPhone under Settings > Messages.
You do not configure this anywhere on your PCs.
You do not configure this for your infant at this point in time.

FaceTime - To avoid confusion, this would be an individual Apple ID for each person.


You configure your Apple ID on your iPhone under Settings > FaceTime.
Your wife would configure her Apple ID on her iPhone under Settings > FaceTime.
You do not configure this anywhere on your PCs.
You do not configure this for your infant at this point in time.





On content sharing between devices, you can use an account with up to 10 devices. Here's what iLounge says based on Apple's policy about "More than five family devices sharing a single iTunes account":


  Actually, the limit of five devices per iTunes Store account only applies to authorizations for computers using iTunes. Apple actually allows you to have up to ten devices authorized in total for features such as iTunes Match and re-downloading previous purchases from iTunes in the Cloud, up to five of which can be computers running iTunes. So in other words, you could have anywhere from 10 iOS devices and no computers up to five computers and five iOS devices or any combination in between. You can view the number of devices that have been authorized for these features by going into your iTunes Store account information from within iTunes and choosing the Manage Devices option. 




To share calendars, see iCloud: Share a calendar with others.
To share reminders, see iCloud: Share a reminder list.