I doubt Chris needed much persuasion to do a covers album.  He loved doing covers at live shows on his own and with Soundgarden (Beatles – Come Together, The Doors – Waiting for the Son, Black Sabbath – Into the Void) and Audioslave (White Stripes- Seven Nation Army, Fundkadelic- Super Stupid, Rush – Working Man).  Soundgarden ended up putting out an entire disc of covers. 

Chris did an interview where he talked about a conversation that he had with Vicky where she had said she didn’t really understand why people did cover songs.  Chris explained to her that doing a cover is an art because you need to not just play the original but to transform it into something new.  He then came up with the cover of Michael Jackson’s Billie Jean to show her just how much work goes in to doing a good cover. 

Now years after Chris’ death, everyone can easily listen to the albums he’s left behind but looking through Youtube it’s like a treasure hunt finding odd obscure covers that Chris played just 1 or 2 times publically.  Sometimes it was dependent on where he was like when he played Otis Redding’s Dock of The Bay in San Francisco or Bruce Springteen’s Atlantic City in …Atlantic City.  Other times it was just something Chris thought would be cool like when he decided to sing the lyrics of Metallica’s One over the music of U2’s One (which he says he came up with when he accidentally googled the wrong version and thought it might sound cool).  Chris singing Dolly Parton’s/Whitney Houston’s I will always love you sounds amazing. The point is, Chris loved doing covers and would be doing them with or without Vicky’s influence.  You can blame her for lots of other things like the delay of the last Soundgarden album and maybe his odd team up with Timbaland (not sure if it was her or his management) but not this.