Let $\mathcal{A}\left(\mathbb{D}\right)$ denote the vector space over $\mathbb{C}$ of all holomorphic functions $f:\mathbb{D}\rightarrow\mathbb{C}$. Define the following norm:$$\left\Vert f\right\Vert \overset{\textrm{def}}{=}\sqrt{\lim_{r\uparrow1}\left(1-r\right)\int_{0}^{1}\left|f\left(re^{2\pi it}\right)\right|^{2}dt}$$ and let $\mathcal{H}\left(\mathbb{D}\right)$ denote the closure of $\mathcal{A}\left(\mathbb{D}\right)$ with respect to this norm (i.e., the set of all functions which are either in $\mathcal{A}\left(\mathbb{D}\right)$ and have finite norm, or which are the limit of a sequence of such functions which is convergent in this norm).

Now, writing $\mathbb{N}_{0}$ to denote the set of all non-negative integers, for any $V\subseteq\mathbb{N}_{0}$, write:$$\varsigma_{V}\left(z\right)\overset{\textrm{def}}{=}\sum_{v\in V}z^{v}$$ I call such a function a “digital function” (its coefficients are $0$s and $1$s), a.k.a. the “set-series of $V$”. Then, define: $$\mathcal{D}\left(\mathbb{D}\right)\overset{\textrm{def}}{=}\left\{ \varsigma_{V}:V\subseteq\mathbb{N}_{0}\right\}$$ as the set of all digital functions.

With these definitions:

(1) Are there any functions in $\mathcal{A}\left(\mathbb{D}\right)$ which are not in $\mathcal{H}\left(\mathbb{D}\right)$?

(2) Is $\mathcal{H}\left(\mathbb{D}\right)$ dense in $\mathcal{A}\left(\mathbb{D}\right)$ (say, with respect to the norm topology on $\mathcal{H}\left(\mathbb{D}\right)$, or with respect to the topology of uniform convergence on compact subsets of $\mathbb{D}$)?

(3) The same thing as (1) and (2), but with $\mathcal{D}\left(\mathbb{D}\right)$ in place of $\mathcal{A}\left(\mathbb{D}\right)$. In particular, what can be said about $V$ if $\varsigma_{V}$ is not in $\mathcal{H}\left(\mathbb{D}\right)$?