General comment: I am unaware of any guitars that use all nylong strings. What I'm used to seeing when someone says "nylon string" is that the bass string (E, A, D) are bronze and the treble strings (G, B, high E) are nylon. Standard Classical guitar setup. I would go with that. The larger bronze strings (or steel) shouldn't cause much finger strain as they're pretty large. That said, I am not an encyclopedia of knowledge about guitars and you may be completely correct about all six strings supposed to be nylon. Just seems a little "Red Rider Guitar Free With Six Box Tops" to me.
1. I would recommend D'Addorio Classical strings.
2. I'm sure someone has a website video handy. I had a guy at my local shop show me how to put them on back when I took up guitar the first time. Bought a book and two sets of strings and had my guitar along. He was happy to help (it wasn't busy in the store at the time).
3. Same way. From largest string to smallest: Low E, A, D, G, B, high E. Lowest string goes on the bottom. Hold the neck in your left hand with the guitar body on your lap, and the lowest strings will be on the upper side of the guitar. If you have the guitar in front of you and you are looking at the sound hole with the neck facing away, the larger strings will be on the left. The strings are labeled or marked. Easiest to tune with an electronic tuner. They're about the cost of two sets of decent strings, so a very small investment that makes life invaluably easier when you start.
Good luck! My daughter has a 1/2 size "folk" guitar that uses nylon strings (half of which are steel) and loves banging on it. I keep it in tune for her so her banging on it is at least in tune. She's beginning to show interest in actually plucking particular strings on purpose. It will be very cool to get past this "Music Man" stage.
- Zurf
Granted B chord amnesty by King of the Mutants (Long live the king).
If it comes from the heart and you add a few beers... it'll be awesome! - Mekidsmom
When in doubt ... hats. - B.G. Dude