Just as the title says. Coco still reacts to Crash being there and laughs when something funny happens with Crash's idle animations but she no longer dances with him like she used to. In addition she also doesn't get irritated with him either. All these interactions can be seen in the video below.
I am currently playing on the Steam version so I cannot confirm if this is the case in other versions.
Unrelated but the cutscene with Cortex that is suppose to play before the first boss in Crash 2 also doesn't play in the Steam version.
I can confirm the cutscene that's supposed to play before the first boss in Crash Bandicoot 2 doesn't play. The reason is that they would have had to write new dialogue since N. Brio's Bosses no longer attack Crash Bandicoot in between Warp Rooms, one of the corrosponding cutscenes related to the first boss fight will instead play after you defeat Ripper Roo and enter the second Warp room. (It would've been helpful to have a new cutscene where Cortex mentions that they have enemies everywhere, Some of whom you may recognize, "make sure to take care of them swiftly if any of them decide to attack after entering a portal"
For some unforseen reason, Coco Bandicoot will no longer be visible in the Warp Room when she's selected as playable. Also, a quick side note, she's irritated at the player for not doing anything, she makes the same face durring one of her idle animations, and when her jetski crashes into explosives. Her face generally aimed towards the screen so the player can see how irritated she is that you are just goofing off, or in the case of the jetski levels, angry that you made her lose a life and got her stranded in the ocean.
On the subject of the first boss cutscene, they did record the lines and animate them. The question is why didn't they just do what they did to the other lines and cover them with static?
The thing with Coco not being in the warp room is intentional though. Imagine trying to switch to her while she's there at the computer. It ain't worth the stress coding.