This television does not have a Twitch application built in.
#3 Does this TV have a web browser capability? Also, can you add additional apps?
To my knowledge it does not have a stand alone web browser. I believe it comes with a suite of it's very own Vizio Apps and does not allow you to add additional third party apps.
#4 Can more apps be added or am I stuck with apps that were installed at the factory?
Apps can be added though the built-in yahoo connected TV store.
#5 How much of a space gap is there between the tabletop/stand until it hits the TV?
The distance between the bottom of the TV and the tabletop with stand is 2.16".