So, the easiest way to differentiate between indoor/outdoor use of elements is indeed making a copy of it and adjust the settings to fit your needs. Copying an element is “cheap” when it comes to file size. As it is using the same samples and only changes the parameters of play, you won’t blow up the soundset unnecessarily.
When you start experimenting with the settings, keep in mind that they might be tied together closely when judging the result. For example - if you use “Stone Dungeon” as reverb, the further you move the samples “away” (aka increase the distance), the more echoy it gets, due to the nature of the dungeon walls reflecting the sound and multiplying the resulting echos. If you choose “Carpeted Hallway” a lot of the reflections will be muffled by the soft surface of the carpets, hence you get a different set of reflections.
Easiest thing is trail and error to see what fits your need. Be bold! 
Angle is pretty self-explanatory: if you set it to “-90 to -90” it is to your left, set to “-135 to -45” it can be positioned to your left, but may be a little bit up front or behind. You catch the drift.
3D positioning is important as to utilize the whole reverb engine. If you don’t allow 3D positioning it is perceived as pure stereo (think move soundtracks - the score is played as a stereo track, whereas effects are always placed in the surround spectrum) - which is an optimal setting for music but not the best for effects.
As for setup - always use what’s best for the setup you use when playing. And - see above for the 3D thing. I don’t have a surround set at my table, but i try mixing it as good as possible to perform well on different output devices. It is a balancing act, but if it sounds great for you on your system, then you should go for it! 
