No, because in this case there is a preposition (we read to them), so an indirect pronoun needs to be used, "Nós lhes lemos um jornal" or apparently also "Nós lemos-lhes um jornal"
I think it could be. But I guess there is a little difference of meaning,
I am not quite sure because I am not a native english speaker, but I was taught that when you are doing something FOR somebody you are doing it in place of somebody, for example: We read the newspaper (to them) for you.
Another example: I give the present to you (the present is yours). I give the present for you (the present belongs to another person and you should give that present, but I am giving it for you).
In portuguese, "for' could be translated to "por" and "to" could be translated "para", in the first example the translation in portuguese would be: "Nós lemos o jornal para eles por você". But most of times, we can translate "for" as "para" too, and the same example could be trasnlated to "nós lemos o jornal para eles para você". In other words, in portuguese, at least in informal way, most of times, "para" can be use to translate "for" and "to" (it would be no change of meaning because the same sentence can mean the two situations) but the opposite doesn't work because in english has a sentence for each situation.