Eric Palmer found the following 3-view of the Pak-FA with descriptions, in French, on a Russian message board.

Well, it shows a number of features, though the provenance is totally unclear.

Items of interest are the IRST in front of the nose(2), wing mounted radar arrays (10), in flight refueling provisions (8), external stores provisions (16), a missile warning system (4), and (most notably) a vertically inclined “S” duct for the engines.

It does appear to match the general configuration of what was seen in the flight video though.

I hadn’t thought about a vertical offset in the inlets to hide the engine face, but from this 3-view, it does appear to be there, so the engine does appear to be shielded, at least partially, though I would still bet on a radar blocking grid.