Would we expect to see Kosuzu, Sumireko, and all of the LoLK cast in future updates?
I suspect that if that were to happen, it won't be for a while.
Not to mention the fact that there aren't even any decent sprites for Sumireko and the LoLK cast (We'd need the Chibi and Evolved (Front and Back), as well as menu sprites). Reimufate's sprites are an abomination, in my opinion, so they don't count.
Let's not forget to mention that not even the Japanese Touhoumon wiki has any updates or unofficial patches that include them. And this is all before considering their typing, balancing, and figuring out what role they would play in the meta that the other 200+ puppets don't already play.
While I'd like to consider having Sumireko and the LoLK cast, I feel there's also been a lack of any new development regarding Touhoumon 1.8 as a whole. Most people that come now focus on TPDP (or are at least waiting patiently for a translation). I'm almost sure there'll never be a Shoddy TPDP server, since it'd take a very ambitious mind to program one (anyone who's up for the challenge, you have my respect).
As for Kosuzu...I'm really not sure why she's not on the server. She does have a battle and menu sprite, but I guess she would be considered Reisen II-tier if she was added.
UPDATE: Apparently Tohofes and PixEvildrake in fact DO have decent Chibi and Evolved LoLK sprites, albeit only front sprites. Somebody would still need to do back sprites and menu sprites. We'd also need permission (In Tohofes' case, if we can). My other points still stand...
Have a gander:Also, is it just me, or does the thing Chibi Doremy is holding remind you of an onahole?