Yes, with a double last name that includes the name Horváth --
the Hungarian word for "Croatian" --
that is a logical presumption.
I did pay attention to the questions to which this gives rise.

My findings are negative.
As the opening post reports,
the birthplace of Lázár Petrichevich-Horváth
was Cluj-Napoca;
this is a population center of Transylvania,
and today I find that it is inside Romania's borders.

You may find an article on the author at Hungarian Wikipedia.
Since I rely on Google to pull up Wikipedia articles,
even though I have no Hungarian,
I can use Google's translate function to read
a rough English translation of the Hungarian Wikipedia article.
Which tells me:

the poet's early education and employment was in
Targu Mures, Sibiu, and obviously Cluj-Napoca.

In time he became a correspondent of the
Magyar Tudomanyos Akademia.

Wherever I find even a brief account of the author's life, one thing is emphasized, and it is not about Croatian ancestry.

It is the emphasis on the author's aristocratic upbringing.
Not only is no mention whatever made of Croatia, or of the Croatian language,
but it seems that he moved in aristocratic circles
where there were more French and German speaking people
and a number of the people were not even really Hungarian at all.
Not to speak of Croatian.

So I guess it is safe to presume
that ancestors must have included Croatians in the poet's case,
but he seems to have inhabited
a really rarefied atmosphere in Transylvania,
then later in Pest,
which did little to prepare him
for life on his own in the real world.
There is a "poete maudit" quality in the descriptions of
the poet's career failures and personal alienations.

Of course, if anybody else finds any information,
even if it contradicts what I found,
then please contribute!

So, no, no sign of this poem in the Croatian language,
to answer your final question, sorry about that.