In addition to what enkidu has already written, there
are lots of direct actions that could be both non-violent and maybe legal - these could be in the form of collecting and sharing food or other items (ala Food Not Bombs or Really, Really Free Market models), copwatch programs, prisoner support campaigns, etc.
However, what needs to be said is that concern about the violent/nonviolent dichotomy, or about keeping anarchist actions legal, is a bit of a red herring. I think the question becomes, why do you want the group to be non-violent and "preferably legal?"
It can, strategically, make sense to begin taking action with others, especially strangers, in relatively safe ways. This allows a person to gauge potential comrades for future actions, and to find those with whom we feel affinity. From there, that group can proceed to take actions, some of them might be legal, some of them might not be, if those people are not just using "anarchist" as a marketing ploy, that distinction will lessen over time.
As to actions that are non-violent - I suspect that as time goes on, the need to distinguish between violence and non-violence as an either/or category will start to fade from black and white to shades of gray, unless the ultimate goal is to build a broad-based movement whose ultimate goal is not a non-hierarchical, egalitarian world [I know, redundant!], but instead a movement which is broad while lacking depth. These groups tend to fizzle, constantly lose members who are not willing to remain shackled by pacifism, or become non-anarchist cadre organizations. Which is to say not really effective or anarchist.
There are anarchists, and movements within anrchism that have maintained a strong pacifist or non-violent perspective. I am not trying to negate or ignore that, but I do think it is important to point out that once a group branches beyond merely symbolic (and ultimately, non-threatening to capital) acts, they will face repression. I will need to leave it up to others to explain why remaining non-violent in the face of this is a universally defensible choice - I don't think it is impossible to have such, but I don't, and would welcome hearing about them.
If I have misconstrued what you are asking, I apologize, and I realize I opened further worm buckets, but it seems like there are some points about why the structure you desire is such that need clarification.