I'm trying to understand definition/work out some examples. So, there are some simple questions about higher stacks.

For the simplicity assume that we are working with higher DM (Deligne-Mumford) stacks over $\mathbb{C}$.

1. Is there some analogue of Keel-Mori theorem about existance of coarse moduli space for higher stacks?
2. It is well known that ussual DM (1-)stacks with a point as a coarse moduli are quotients of a point by a finite group $G$ acting trivially, and coherent sheaves on it are just representations of $G$. So, what are the higher DM stacks, whose coarse moduli is just a point? What are the categories of coherent sheaves on such stacks?
3. What are the higher quotient stacks? What are the coherent sheaves on them? For example, what are the quotients of $\mathbb{A}^1$?
4. It is well known that ussual DM (1-)stacks etale-locally are quotient stacks. Is there some analogue for higher stacks?