Isomorphism between two universal p-typical formal group laws EDIT: I've tried to alter the question so that its basic nature is clearer, as it's been unclear to a number of people now.
At any prime p, there is a graded polynomial ring $V \cong {\mathbb Z}_{(p)}[v_1, v_2, \ldots]$ carrying two formal group laws.  These formal group laws are of the form
$$
F(x,y) = \ell^{-1}(\ell(x) + \ell(y))
$$
for a logarithm $\ell(x) = \sum \ell_n x^{p^{n+1}} \in ({\mathbb Q} \otimes V)[\![x]\!]$ (where $\ell_0 = 1$ by convention).  Both of these formal group laws have the property that they are universal among so-called $p$-typical formal group laws, and see heavy computational use in stable homotopy theory.
These two are based on choices of recursive definition for the logarithm coefficients in terms of the generators $v_i$ of $V$.  The first definition (the Araki generators) satisfies:
$$
p \ell_n = \sum_{k=0}^n v_k^{p^{n-k}} \ell_k = v_n + \ell_1 v_{n-1}^p + \cdots + \ell_{n-1} v_1^{p^{n-1}} + \ell_n p^{p^n}
$$
The Hazewinkel generators are instead defined by:
$$
p \ell'_n = \sum_{k=1}^{n} v_k^{p^{n-k}} \ell'_k = v_n + \ell'_1 v_{n-1}^p + \cdots + \ell'_{n-1} v_1^{p^{n-1}}
$$
This gives the ring $V$ with two logarithms $\ell$ and $\ell'$, and two distinct universal formal group laws.
My question is: Are these two formal group laws isomorphic?  Strictly isomorphic?
ADDED: Since the ring is torsion free, any isomorphism between them is of the form $f(x) = (\ell')^{-1} (c \ell(x))$ for a unit $c \in \mathbb{Z}_{(p)}^\times = V^\times$.  They are therefore isomorphic if and only if they are strictly isomorphic.  Therefore, the question is equivalent to the following:
Does the power series $(\ell')^{-1} \circ \ell$ have coefficients in $V \subset V \otimes \mathbb{Q}$?
(The issue was brought up when thinking about truncated Brown-Peterson spectra ${\rm BP}\langle n\rangle$, whose rings of coefficients are $V/(v_{n+1},v_{n+2}, \cdots)$.  It then becomes a question as to whether these are equivalent as ring spectra depending on the choice of generators.  There are certainly different choices of generators for which they are inequivalent.)
 A: As a way of additional information - explicit expressions of the $l$s in terms of the generators look like this:  
for Hazewinkel generators,
$$
l_n=\sum_{\substack{n_1+...+n_k=n,\\1\leqslant k\leqslant n}}\frac1{p^k}v_{n_1}v_{n_2}^{p^{n_1}}v_{n_3}^{p^{n_1+n_2}}\cdots v_{n_k}^{p^{n_1+n_2+...+n_{k-1}}}
$$
while for the Araki ones,
$$
l_n=\frac1{p^{p^n-1}-1}\sum_{\substack{n_1+...+n_k=n,\\1\leqslant k\leqslant n}}-\frac{(-1)^k}{p^k}\frac{v_{n_1}v_{n_2}^{p^{n_1}}v_{n_3}^{p^{n_1+n_2}}\cdots v_{n_k}^{p^{n_1+n_2+...+n_{k-1}}}}{(p^{p^{n_1}-1}-1)(p^{p^{n_1+n_2}-1}-1)\cdots(p^{p^{n_1+n_2+...+n_{k-1}}-1}-1)}.
$$
I would not object if anybody finds this uselessly horrible --- such people may view this as a joke.
Then for the latter, as an additional joke, note that because of these expressions the following becomes tantalizingly close to being true:  
Araki's $v_n$ is ``almost'' equal to $-\frac1{\sqrt[p^n]{p^{p^n-1}-1}}$ times the Hazewinkel's $v_n$ :)
A: I happened to see your question. And I don't know whether you've found a good reference. You may want to have a look at Haynes Miller's notes on cobordism. Below is a link for that:
http://www-math.mit.edu/~hrm/papers/cobordism.pdf
The answer to your question is YES. It's discussed in the 5th section of Chapter 2 in the note.
A: No, at least when $p=2$ the coefficient of $x^8$ in the relevant power series is not 2-locally integral.  I have put a Maple worksheet at https://strickland1.org/misc/ArHaz.mw with a PDF version at https://strickland1.org/misc/ArHaz.pdf.
