My research OCD has started to kick in again and I've been doing more searches on whiteboards. It seems this ghosting issue is the big problem, and some - though not all - have found it to be a problem on melamine boards. Polypropylene seems like the best bet for a full wall solution. Though for long term heavy use, the ceramic boards are starting to make sense; they last indefinably and have zero ghosting.

Now that I have received my degree in Whiteboard Science from the University of Google, my recommendation for MIRI is this: purchase one or two ceramic whiteboards for heavy daily use and then buy polypropylene (in terms of ghosting, it is almost as good as ceramic) for the remaining walls.