It's double trouble 1, so it's not like you're getting an insane burst of stats like you would from 2 or 3. Still great not like it's guaranteed first.

DF emblem is sort of a waste of a gold augment here and gold augments are giving everyone the most power with the other silver augments. It's netting you nothing except the essence but you already had shimmer spat... And while essence is amazing to the comp, you only need one and it could have been something more valuable like cav/sin/cannon spat anyway. One of them is not the worst trade in the world for essence but is just not optimal. Or you could change up your team to add Graves/Nilah/legendary or something over the rell or aphelios to not sit at 7 DF, might save you some gold rolling for aphelios 3. Might even be worth some quick math if you had a chance between a real combat augment like Knifes Edge plus DF'ing an actual item or worthless emblem plus DT1 (without the other emblem already). All things to consider in comp structure.

With essence, Swain and Rengar 3 should be at three items, you want everyone else to die before them to feed them stats. You don't want Rengar or Swain dying first to feed your shitters stats, you've probably already lost the fight at that point. That GA on rengar 2 would've been awesome on rengar 3 and warmogs could have been big on swain.

Speaking of shitters dying, the aphelios items are probably worst in slot, he's too tanky to die and feed rengar but you want him to ideally get a big burst of damage out then be one of the first to die for Rengar/Swain stats or finish up the fight if things go awry and rengar gets targets first. Last whisper is great on him or rengar to enable some damage especially into tankier comps.

Morello is king on Swain while the rest of the comps items are fairly flexible. And definitely into jades, healing reduction is huge.