Yes, the Nexus tablets (Nexus 7 and 10 currently) allows for texting, provided you are connected wirelessly or have a Nexus tablet that has cellular capability.
This unlikely will not work as iOS and Android apps are not compatible with each other.
Yes, through Google Play and the Amazon Appstore.
If you do not like the keyboard choices that came with the Nexus 7, you can download third-party apps such as SwiftKey, Swype, Emoji, and others.
There's currently no iTunes app for the Nexus 7, or for Android OS in general. However, there are various syncing apps where you can sync downloaded content from iTunes to any Android-powered device, which includes the Nexus 7.
You can either look at it thru the Play Store app (My Apps), or under Settings > Device > Apps.
From what i know the app store is a lot better than the kindle fire. The nexus 7 has around 800,00 apps compared to Amazon's 600,00 apps. Amazon has popular apps but not much important apps. Other than than that i don't really know anything else the nexus 7 can best the kindle fire at. The graphics and sound on the kindle fire HD is just AMAZING. So yea......hopes this helps!
With fairly high-end specs, a competitive pricepoint, and a "pure" stock Android operating system built in, the Nexus tablets (both Nexus 7's and Nexus 10) are considered good buys.
Checking on amazon there is a nexus 7 tablet on sale for $230.18 there are many others models but this one is one of the more affordable tablets on the market.
You can get apps in Google Play store.
KitKat (Android 4.4 OS) is rolling out to the Nexus series of tablets (Nexus 7 2012-2013, and Nexus 10). There's no ETA as to when the OS will roll out to other tablets at this time. There are developers making a customized ROM of KitKat that would likely rollout ahead of an official update.
Office have not been released for android. You can use apps like GoogleDrive.