An update about my ghosting problems.
It's the cable integrated into my monitor. I tried with another monitor and the output was just fine. At least my board seems to be okay.
Then I did some experimentation. Took a gender changer block and added another sturdy VGA cable between the Amiga and the Integrated VGA cable. Unsurprisingly enough, the image looked even worse. Then I changed the extra cable to something that came bundled with a flatscreen monitor, thin and doesn't look so great. Now the ghosts are gone. The screen is a bit blurrier though.
This is not something I know a lot about, but a theory was put forward to me that the difference of impedance between the flat-cable of the Indivision and a good VGA cable may cause the signal to echo at the junction. A better cable for the Indivision might be a good fix.
I have a 2B motherboard with a CBM Lisa, and installation was easy. Didn't need insane force to click in place and doesn't wobble. I later took it out and put it back using a lot of strength, but I don't think it's seated any different now.