I can't find any evidence that the 3 active accounts have been traded since that particular transaction. From 2015-2017, they tended to post in the same subjects and have similar gaps in posting.
After the date of the transaction, their style continues to share some similarities although he does a good job of sticking to all lowercase for figmentofmyass. Also, little things like this (I have many examples) make me think they're still all owned by the same person. The only 2 search results on the forum for the phrase, "some from Column A and some from Column B":
Probably some from Column A and some from Column B.
I think it'll be some from Column A and some from Column B.
Here's the 3 results for "strong monetary properties":
Another good example is this one. This guy said, "as they say", so I wondered who does he mean by "they" because I've never heard the expression said that way before. It turns out it was himself.
as they say, the trend is your friend, until it ends.
The trend is your friend until it ends.
Again, those are the only 2 results for that phrase on Bitcointalk.
If that isn't satisfying enough, the cherry on the top is the merit transfers among the accounts. The merit system wasn't introduced until January 2018, which is after the transaction linking them together occurred.
To/From merit transfers (just some examples, not all of them)1/26/2018 10:18:54 PM manchester93 (Summary) MAbtc (Summary) 1
2/8/2018 3:00:00 AM manchester93 (Summary) exstasie (Summary) 2
2/11/2018 9:00:25 AM romani245 (Summary) squatter (Summary) 1
2/11/2018 9:06:56 AM romani245 (Summary) exstasie (Summary) 1
2/11/2018 9:22:06 AM romani245 (Summary) figmentofmyass (Summary) 1
2/11/2018 9:54:39 AM manchester93 (Summary) romani245 (Summary) 2
2/11/2018 9:59:48 AM manchester93 (Summary) squatter (Summary) 2
8/27/2018 1:40:32 AM manchester93 (Summary) illyiller (Summary) 1
5/22/2019 6:48:46 AM illinest (Summary) illyiller (Summary) 2
10/18/2019 3:55:01 AM figmentofmyass (Summary) marky89 (Summary) 1
10/26/2019 4:10:37 AM marky89 (Summary) exstasie (Summary) 3
1/13/2020 9:01:42 AM illinest (Summary) figmentofmyass (Summary) 1
1/14/2020 7:16:25 PM MAbtc (Summary) exstasie (Summary) 3
1/14/2020 7:46:39 PM MAbtc (Summary) exstasie (Summary) 10
2/8/2020 4:36:37 AM squatter (Summary) figmentofmyass (Summary) 1
3/30/2020 11:37:40 PM exstasie (Summary) figmentofmyass (Summary) 1
Given the fact they were exchanging merits as recently as 3/30/2020, I would say its likely they are all still owned by the same person, especially as there's no reason to suspect any of the accounts have changed hands.
Also, exstasie is in DT2 right now and figmentofmyass is on DT1 with -3 inclusions.