I played Shadowrun Retruns as an orc rifleman, Dragonfall as a human Rigger/Decker, and now I want to try an elf Shaman. What etiquettes help the most throughout the general game, and what is the highest spell level? I'm aiming more for support spells and Acid Bolt, and not spirit summoning. I'll go for the Leapord Totem(I think that's the one with the +1 movement and armor passive effect), but nothing beyond that.

On a final note, does the extended edition come with more in-game missions or does it just add downloadables like wallpapers and soundtracks?

Yes: 6+ hour bonus campaign - Shadows of Hong Kong.

Etiquettes are a bit more spread out than Dragonfall, and I think most important etiquette checks can be passed with high enough charisma instead (which you should have as a shaman).

That said, I believe gang, socialite and security allows you to bypass fights here and there. Academic can lead to bonus funds in one (or two?) places, as well as bypassing one fight IIRC.

HK often has more ways to "solve" encounters than etiquettes - apart from higher charisma (mentioned above, and which DF also had in most places), sometimes other skills are used, such as unarmed/strength (to intimidate someone for example), and sometimes things change based on companions you bring with you to the mission.

As for the extended edition - IIRC there are 6 missions, plus two new hubs to visit between missions.