Using 'for' as a coordinating conjunction at the beginning of a sentence – is this acceptable?

You are right that for is a coordinating conjunction, the first of the so-called FANBOYS. But you cannot move a coordinated clause (starting with a FANBOY) to the front of a sentence:

I was hungry, so I ate.

*So I ate, I was hungry.

It is the same in German:

Ich habe gegessen, denn ich hatte Hunger.

*Denn ich Hunger hatte, habe ich gegessen.

However, you can move a clause with a subordinating conjunction to the front:

Because I was hungry, I ate.

Da ich Hunger hatte, habe ich gegessen.

For, as a coordinating conjunction, is rarely used to begin a sentence, for its function is to introduce the reason for the preceding clause. Putting the reason before the preceding clause makes it awkward, unless you use one of its substitutes - because, or use and after the comma.

For I was hungry, I ate lunch.
For I was hungry, and I ate lunch. (doesn't stand alone well, and sounds antiquated)
Because I was hungry, I ate lunch.

There are, however, well known sentences beginning with that (in essence) 'coordinating conjunction':

For I was hungry and you gave me something to eat, I was thirsty and...
For all have sinned, and come short of the glory of God...

For is more common as a preposition, and much easier to use as a sentence starter:

For most of Haiti's citizens, living conditions are very bad.