"Tsubasa" is definitely a combination of all the girls introduced, but author's definitely also panelling things in a way to make the reader believe so.
If nothing else, I'm betting on Mitsuha being primary makeup artist disguise planner + personnel dispatch at this time (I'm guessing she's listening in on the conversation remotely).
Shiki is a "playmaker" that steers situations in ways desired (hugging MC from behind to introduce herself just as he notices something, readily agreeing to MC friend's idea to get him killed after forcing herself into conversation). She's also the failed "murderer" of MC's friend earlier, though I'm assuming that's more to have Kokushou earn trust. May be at actual odds with "Tsubasa", but not known for sure at this time.
Kokushou is probably the primary lure.
Ogura is probably the one that executed the first shown murder (not enough details so pure guess, and she's going to be relevant at some point).
I assume all get a thrill of sorts from what they do, are heavy liars, and take turns pulling off a kill. Other girls haven't been properly introduced yet to really clue in on what's happening. That's my guesses at least.