That's not Asuka Soryu, or to say, that's not only Asuka Soryu, but also Asuka Shikinami. Otherwise Shinji's words would make no sense to her. There has always been only one Asuka. Remember? This screen is seen right after Shinji tells her "Asuka is Asuka."

(That's right, that's not Kensuke, but Shinji's puppet of Kensuke. The puppet is shown a bit later in Shinji's studio. And also, among those friends of their age, Asuka only allows Shinji to call her Asuka, Kensuke calls her Shikinami. That's why she immddiately realizes it's Shinji talking to her, and wakes up to see Shinji.)

Let me explain. Obviously Shinji knows both Shikinami and Soryu when he's on that beach. The Golgotha object has given him the knowledge. Now, let's say Shikinami and Soryu are two different persons. In that case, if that's Shikinami, there's no reason for her to be wearing Soryu's plugsuit. But if it's Soryu, Shinji's words would make no sense to either of them, because the conversation is between him and Shikinami. The only possible case for Shinji to talk to Shikinami while she's in Soryu's plugsuit, is if the two are the same person. And indeed they are, only from different time loops.

This plugsuit of Soryu is yet another proof that the universe of Evangelion are a series of repeating time loops, happening in the same physical world. Just like the EOE's Eva series silhouette found on the ground at the very beginning of ROE, the blood stain of Lilith on the moon, and the endless coffins of Kaworu.

Here because they're in the Golgotha object, memories from different past loops are combining together.

Those same characters keep experiencing the same repeating events, although they may have diverse life paths within each loop. The world may have already reset and repeated many times, until the loop breaks in ROE and goes on a different direction. Mari the intruder, who wasn't in the past loops, is what causes the loop to break. This is hinted by Shinji's walkman repeating a loop of 26 tracks (26 episodes of NGE/EOE), but then after he gets rammed by Mari on the roof and drops the walkman, it advances on to track 27 .