Well...
My listing of minor-league transactions shows Lartigue assigned to the Alternate Site on 7/18. Zolecki tweeted the same day that Lartigue had been removed from the Player Pool.
So I went back to the minor league transactions listings - and Lartigue is no longer listed as assigned to the Alternate Site. But he's not alone in that - Alec Bohm and others have disappeared from the transactions listings as well. But they were there when I posted them (I don't type in those transactions - I copy and paste them from the milb.com transactions web pages).
All I can conclude is that, for whatever reason, MLB has decided to obscure things, and they've had a bunch of transactions listings removed. Given that, there's no way I can maintain the Alternate Site roster I posted above.
So, unless I can find a reliable source of information (or unless somebody can direct me to same), I'm not going to kill myself on this. To put it bluntly, "A pox on all of them." I've deleted the roster I posted - I have no confidence at this point that anything on that list is reliable.