How to avoid the dangers of gain and honor (lābhasakkara)? It's said that desire for gains as intention for one undertakings, beyond simply that for liberation from suffering, is a huge hindrance, obstacle.

No, the Buddha also warned even Arahats, at least in regard of the accumulation of sakkara (honor, amassing honor, Labāsakkara), as being a cause that leads to unease.

Now, what could, should one do, should avoid, that all kinds of such accumulations do not take place and do not endanger ones intention, aspiration, to bend from highest path and fruits, awakening?

Which role does maccharia (stinginess of five kinds and one primare cause) plays here, and if related, what kind of practice would work against such?

(Note that this task is not given for trade, exchange, stacks or entertainments but just to bind toward liberation)
Now, what could, should one do, should avoid, that all kinds of such accumulations do not take place and do not endanger ones intention, aspiration, to bend from highest path and fruits, awakening?

That sutta implies that even accumulating dung can be a problem for some.

So I'm not sure it's feasible to solve that by avoiding literally everything (especially for a house-holder, but presumably mendicants too -- the sutta seems to be addressed to bhikkhus, not to arhats) -- even including, for example, "food" and "honours".

Instead the problem seems to be in the mental attitude toward accumulation, for example:


"With a mind overcome and overwhelmed by possessions, honor, and popularity"
"they look down on other good-hearted mendicants"


There are other suttas nearby on the same or similar theme -- for example, SN 17.3 offers,


  Whoever enjoys and likes arisen possessions, honor, and popularity is called a mendicant who has been pierced with a harpoon


I suppose the problem originates from the delighting in such things.

Perhaps the sutta itself suggests one of the remedies -- if you see (view) it as being like dung, not nourishing, then you might not be inclined to accumulate (eat) it.

And, as you pointed out in a comment, SN 17.30 says,


  We will give up arisen possessions, honor, and popularity, and we won’t let them occupy our minds.