Do pacifists work: No, not really
To my great regret, I've had experience playing a pacifist. The problem with the pacifist is that it explicitly declines to engage meaningfully in the focal point of the game. D&D, fundamentally, is about interesting combats. While there are certainly groups that provide increased out of combat conflict, the empashsi of design and the rules is on combat.
A pacifist, to be true to character, must seek to decline combat. While in combat, they must not contribute. Therefore, they're kinda sitting around going "well, why am I here?" It is not particularly fun, in my experience. Acting as a negating influence also increases the irritation of other players: when a pacifist successfully negates the need for combat, the rest of the party is sitting around bored.
Furthermore, the concomitant increase in skill emphasis (I recommend the shaman's Speak with spirits) oddly leads to less spotlight time: being successful in all or almost all skill rolls means that no interesting failure occurs. Without interesting failure, scenes pass quickly without a hitch, tension, or drama.
A pacifist in most 4e parties, therefore, is someone who: avoids combat, cancels combat, and tries to minimize the consequences of the rest of the party's actions. They also produce an increased load on the rest of the party, as the lack of damage dealing intentions (much less capabilities) means the rest of the party either needs to do more damage or have combats drag on longer.
I regret that character quite a lot, really.
To be fair, pacifists can absolutely work in games where the central focus of the game isn't combat. But if the game isn't combat focused, 4e is not the right system for you.
Skill focused characters
It is extremely trivial to make absolute-skill-focused out of combat characters in fourth edition. It's just a bad idea. If you are engaging in a game with a significantly above average amount of skill use, it is better to be a jack of all trades than a master of all trades. As master, the DM will either increase skill DCs to compensate or you will never fail a roll. Both outcomes are poor for entertainment's sake.
By building a jack of all trades, you can engage in any skill challenge presented to the party without feeling like a useless character without feeling the inevitable ennui of god-moded success. A shaman is an absolutely fantastic skill-focused character with their Speak With Spirits power. If you take that power, however, try to make sure that most of your skill successes will hit hard DCs around 60% of the time.
Thieves also make fantastic skill-focused characters as they have a number of class features which provide additional skill successes on extremely good rolls and fascinating utility powers.
The only item needed to make someone an effective "pacifist" in 4e is gloves of the bounty hunter:
When your attack causes a target to be reduced to 0 hit points or below, and you choose to knock out rather than kill it, the target is restored to 1 hit point after an extended rest (normally this occurs after a short rest.
With these gloves, there is no penalty for KOing enemies instead of killing them, as they won't be joining the next fight after a short rest. You can then engage in "combat" as normal, flavouring all your attacks as "non-lethal" (a concept that doesn't exist in fourth edition) and indicating that you knock enemies out and take them prisoner. You will, therefore, continue to participate in the entertaining activity of the game and assist your party in the idiom to which they have been accustomed. By phrasing your requirements to "never take a life" rather than "not engage in combat" you can still fundamentally play 4e without the cognitive dissonance or doublethink necessary to rationalize a "pacifist cleric" accompanying a genocidal bunch of standard adventurers.
If your character concept goes through this route, ask your GM to grant you the magic item as a class feature at the expense of being able to land a lethal blow. It doesn't fundamentally change the dynamics of the game and it's a fantastic and flavourful element of a character.
An effective out of combat character will have their feats focus more on upping their bad skills and increasing options (like cheaper rituals through the vistani feat line) and the skill power feat. This sort of character then becomes useful in any situation.