I never put together the whole "deleted embarrassing /intimate messages vs. leaving the nudes and other embarrassing stuff...interesting.

NK and CW leave most embarrassing data like nudes but they thoroughly delete most of the other "regular" phone history data between them with the context of their conversations leading up to the murders. I think that suggests those may have been legally compromising and why she has the forethought of specifically searching on whether law enforcement can retrieve certain communications. She searched on whether she can evade LE capturing her text communications with Watts not their nude imagery.

This made me wonder, too, and maybe you know? How did the cops get all the hokey cards and notes cw wrote to nk? Did she hand them over?

Yes NK handed non incriminating things from him over to investigators since their affair was already confirmed and out in the open.

And if she did- why hadn't she tossed them if she was just trying to "purge that yucky liar" from her life, because he hurt her feelings by lying about his wife and their pregnancy?

Destroying evidence of their communications history thoroughly together that didn't seem to be about concealing their affair that was already known, or the nudes or hokey and may provide some context for what NK and CW decided to toss and what not.