You should be able to set the color to what you want. With the border, I think you just need to add some padding to the ion-card. The card by default has rounded corners so it is cutting off the input border.
In regards to opening an issue, you could but my feeling, being a pretty obscure issue, it probably won’t get addressed soon. I am just a community member so I could be wrong as I don’t speak for the Ionic team.