1. I'm thinking you're referring to a wire tail brace system. Many models do incorporate them into the design mostly on larger faster aerobatic planes and biplanes. If your plans or instructions don't call for them (few trainers do), a good rule of thumb is....if it isn’t broke don't fix it. Also keeping your model lighter by minimizing additional unnecessary tail weight is the highest priority.

2. Rubber band mounted wings are not meant to move around in flight but tend to forgive more in the event of a cartwheel on landing or take-off. However I've seen a rubber band mounted wing bust apart the fuselage upon ground contact as well. A bolt on wing is cleaner and less fuss but often breaks more stuff on a less then perfect wheel down landing. That said nothing can be built entirely crash resistant gravity just plain sucks, wheels make for better landings then wings. If you do manage to figure out the crash resistant engineering dilemma you'll be worth billons.
In my opinion rubber bands suck they must be cleaned after each use and stored in talc powder they're usually more trouble then they are worth. The learning curve for safe wheel down landings is often short with a good instructor thus minimizing wing strikes. So if you have the option to bolt that wing on do it. You can also do it later after you solo but that is also a hassle once it's built and covered.

3. I've been flying RC for 30 years and of the hundreds of flights and models I've only seen 2 fly away. One was a larger gas model during flight the battery pack died. It flew completely level until it could no longer be seen. Days later in town at the dinner a neighbor living about 7 miles north of the field asked "if we lost a model the other day"? We said, “yes did you find it”? He said, “yep seen it flying over my house about 300’ flying level still heading north until it was out of sight”. It was never seen again likely flew 2 counties away with 40 minuets worth of fuel dead calm wind. The other was a smaller towed glider taken away by high winds never found. Often when things go bad planes never go up or fly flat and level. Unfortunately Murphy's law works fast by smacking a plane hard into terraferma instantly rekitting your model never far from the field being quite easily found with the obvious debris.

Save that GPS money and buy a good quality PC flight simulator the skills built flying one of these units are far more valuable. When trouble does happen with many simulated flight hours you'll have a greater chance at recovering with lightning reflexes that are as instinctual as breathing. Practice makes the hands work with little thought even real pilots know this fact, it's crazy how habit works on the brain so try to build good ones.