mdd: tax credits, child allowance and havtachat hachnasa are for all. its nothing specific to chareidim and is not income dependent. Now, you want to ask if its hashkafically correct to take havtachat hachnasa? Thats a difficult question which I don’t want to get involved in. i will say this, though; I don’t think its prevalent to take it. I personally only know of one family who does take it.
At least i can see you have some value for talmud torah which unfortunately is glaringly missing from some of the other posters here. Gadol sinas am ha’aretz l’talmidei chachamim – and it shows.