Here's my take: I'm with Derrel..... I really don't see much issue with them. Given a full-size JPEG, or better yet a raw file, I have no doubt you could make them look like how you want them to.
Your camera settings are fine.
Camera Maker: Canon
Camera Model: Canon EOS REBEL T3
Lens: EF-S18-55mm f/3.5-5.6 IS II
Image Date: 2017-03-22 11:46:07 (no TZ)
Focal Length: 39mm
Aperture: ƒ/18.0
Exposure Time: 0.167 s (1/6)
ISO equiv: 400
Exposure Bias: +0.33 EV
Metering Mode: Matrix
Exposure: aperture priority (semi-auto)
White Balance: Manual
Flash Fired: No (enforced)
Orientation: Normal
Color Space: sRGB
GPS Coordinate: undefined, undefined
Software: Windows Photo Editor 10.0.10011.16384
They're a bit underexposed, but that's to be expected when shooting what we visualize as being white paper. The camera will always try to make pure white look more like your 18% gray card. Adjusting your Exposure Bias to +0.67 or +1.00 will help.
You say you tried a gray card? What process did you follow from taking the photo to adjusting the WB in post? Did you use a raw file, or JPEG?
Also, is your monitor calibrated?