To answer your questions:
1. Yup.... if you get panicky, just flick your switch up to P-GPS and the Inspire will slam on the breaks and hold in hover (assuming you have let go of the sticks)
2. Yes - as long as home point has been set when you take off the RTH will work in either mode
3. Oh horizontal... vertical is wayyyy too easy

... Imagine you were flying your Inspire at 50 ft up and you were positioned 100 ft up above it. As you look down you would see the shape of a figure as the route you should be flying - but with the nose always pointing in the direction of travel.
Like this (although it's on a heli you will get the idea ->
Oh..... and don't worry about the inverted figure eights !!!!

- It can't be done on a quad unless it has collective pitch and not fixed pitch like the Inspire..... so ignore that bit.
And yes... panic can do nasty things to the adrenaline levels and the heart rate

. Just remember, if you loose orientation (and it is easy to do at distance), just flick to GPS, regain your composure, bring the bird back to you and start again.
One thing about distance is once you get to a certain footage away from you it becomes very difficult to tell if the craft is moving towards you or away from you. There are some tricks you can learn to regain your orientation and tell exactly what direction the craft is pointing at distance but I'd get confident first at Atti flying.
Also, as you say..... there is a lot of information available to you on the screen and you always have that straight line that points direct to where you are standing (home point) as well as the radar screen in the corner that will give you an indication of which way to turn to get back home (you are the center of that radar screen)
Keep at it.... It will click and you will have a big grin on you face that you can do nose in flying comfortably without worry