This is a bit confusing. We are not comparing multiple cameras to each other to see which one is better or test single lens on multiple bodies to see if a lens faulty. The test here is to make sure that 3 groups of sensors on a single camera operate equally well.
All you need for this is, ideally, more than a single lens to show that any particular lens is not an issue here. A well light environment, set of flat targets (star charts or anything else with fine details), tripod and a remote control to avoid any possible shakes (if you can get really fast shutter speed then remote is not really needed). And that's it. It's not a rocket science. The process of doing that is outlined pretty well by such well known photographers as Thom Hogan and Nasim Mansurov.
No need to bring into this ideas like "color temperature" and such. It's simple - if one (or more but not all) sensor groups do not focus properly using Phase Detect but focus properly using Contrast Detect on more than one lens then it's extremely high probability that the camera body is the issue.
In addition to flat targets I would also test focusing on some non flat object making sure that focus point is always the same - then it's another example of how focusing affects the image in real world scenario.
To those who would say "stop shooting targets and go into the real world" - unless you shoot everything at f/22 focus precision is important.
Why do people try to confuse those who have problems and make it seem like the issue is with the person? Would these same people appreciate if someone more knowledgeable in another area started to confuse them with a lot of irrelevant details? The attitude of "you don't know what you are doing" is really annoying and arrogant.