HAHA!
Last time the Clues Abound quest was up, I followed the hints presented in this comments section. I went and found the Hearthstone card, I completed the Clues Abound quest and picked up the Time for Heroics. I then farmed the [npc=152653] and the [item=168256] dropped according to plan after around 20-30 kills. Encouraged by the comments here, I then went and rescued [npc=153538], picking up the Deck 'Em and then went and farmed [npc=150698] for FOUR (4) hours (while binging Stranger Things 3) without the [item=169864] dropping - I checked again and again that people have commented that both can drop for you on the same day and in the described fashion. At last I gave up and went to bed.
Today the quest is up again. Again, I went and found the Hearthstone card, I completed the Clues Abound quest and picked up the Time for Heroics. Again, I rescued [npc=153538], picking up the Deck 'Em and settled in for some farming.
The [item=169864] dropped on the first [npc=150698]... I shouted out "Are you f***ing kidding me?" and my family came rushing to check on me. Then I went here and wrote this and now I will go get my Outside Influences achievement. Well deserved!