Both sensors are knock sensors, the oe one (first sensor pic) and an aftermarkt one for the knocklink. Both need to be bolted securely to the block. The bottom pipe on the header tank attaches to the black crossover water pipe, you should have a curved water pipe to mate the two. The other pic (pic 2) looks like one of the crankcase breather outlets, (iirc) this connects to a sort of y connector (black pipe with 2 inlets on one side and 1 outlet on the other) with a small breather pipe.
Johnny