As for the Adieu remix it actually sounds like some brass preset and the second one sounds like saws with perhaps some other waveforms or some fm or whatever - doesn't really matter because that sound comes mostly from a filter envelope (highpass in the second example?). When you get a harmonically rich sound (nice high mid/highs especially!), set amp envelope to mid/longish attack and some release too. Play with the filter envelope. The first track has a slow release sidechain, probably to a muted kick, that way the synths duck the same amount to kick and snare.
I tried recreating something similar but usually it happens by accident
Would like to see a tutorial from someone who made it sound this good. However it would be basically giving away the whole idea of the track so I doubt that