I think the rules for the sophons are not entirely clear, because he set them up as a plot device for a few of the things he needed (FTL, no more science, omniscience of the enemy) in order to create the special conditions that force humanity to defend itself by creative thinking and this is also why I didn't spend too long cross-referencing their viability. Nevertheless I vaguely remember them being some kind of giant PCB when unfolded in 2D with a fairly high level of abstraction and autonomy without being strong AI (and therefore a new civilisation). It's a given in the plot anyway that you don't want to create a higher civilisation, because of the DF... well, I'm not going to spoil it, but the Trisolarians have very good reason not to create real intelligence capable of resetting its goals.

The translation is as good as it's going to get. The main issue is that Liu is from the PRC and spent most of his life there. It took me years in Asia to slowly realise how differently the Chinese think from Westerners (hell, Westerners themselves think very differently just across borders - compare the worldview of a Brit to that of a Nordic or a Frenchman). If you compare Strugatsky and Asimov, you also get this huge cultural difference that is untranslatable because of the large amount of metadata bagage that Russians would already have coming into Strugatsky's work after growing up in Russia.

The book is "very Chinese", if that makes sense, which I think is what confuses people (and to me is a feature). A quick intro to what that means might be watching a few episodes of If You Are The One (非诚勿扰), a slightly crazy dating show that since the second season has had a government censor added to the panel to moderate the gold diggers; an Australian TV channel has started subtitling a bunch of episodes, although I unfortunately could never find the infamous season 1 ("I'd rather cry at the back of a BMW than smile on a bicycle"). You both get a sample of PRC normal citizen thinking and a taste of how the government is setting the tone culturally.