Yes on iOS 5 and up
It disapeers
Yes it come with Messages
You can recover deleted iMessages on your iPad using MobiKin Doctor for iOS. Here’s how: Recover iMessages with MobiKin Doctor for iOS 1️⃣ Download & install MobiKin Doctor for iOS on your computer. 2️⃣ Connect your iPad via USB and launch the program. 3️⃣ Choose Recover from iOS Device and scan your iPad. 4️⃣ Select Messages and preview the deleted iMessages. 5️⃣ Click Recover to restore them. If you have an iCloud or iTunes backup, you can also use MobiKin to extract and recover messages from backups without overwriting your data.
To add people on iMessages, open the Messages app on your iPhone or iPad, then tap the compose button (a pencil inside a square) in the upper right corner. Enter the recipient's phone number or Apple ID email address in the "To:" field. If the person is in your contacts, you can start typing their name, and it will auto-suggest. Once you've entered the details, type your message and hit send.
There is no App called imessages. It's just called Messages and it is a white text bubble on a green background.
iMessage lets you send messages back and forth with anyone on iPad, iPhone, or iPod touch. Send photos, videos, locations, and contacts, too.
iPhone indeed supports sending pictures via MMS or iMessages. If youriPhone won't send pictures in text, my guess is you don't have MMS enabled on your phone. Also, this problem may be caused by the network, the carrier and so on.
Ipad
Do you mean iPad? iPad are bigger than iphones.
iPad 3 (or iPad Retina Display) is out yes. iPhone 6 is not, but iPhone 5 is.
There are apps you can download like bluetooth IM which uses BlueTooth technology to send a message from ipod/ipad/iphone to ipod/ipd/iphone.
No, the Apple iPad Dock will not work with any iPhone.