Welcome back! A few (not exhaustive) comments:
-- Wavefolders: Intellijel Bifold is super IMO. A little more HP but worth it. 4HP solid options IMO include Joranalogue Fold6 and Instruo Athru. I own all of those (I'm into wavefolders). Still logging time on them and getting to know them, but think they're all good!
-- more vs. less sound sources you ask? Generally, in a medium sized rig, less sound sources, and percussion handled elsewhere (as with your Rytm) as possible. Modular requires a lot of "supporting modules" and in a small to medium sized rack, too many sound sources will crowd out the "supporting modules" and lead to an underperforming total rig design.
-- case? Your build above is mostly full. Best if you can start a build leaving some room to add / grow. But tempting to fill the case early on (which I'm also guilty of). For consideration: your setup is likely to change / grow over time. Investing in a case that that leaves you room to grow is usually a good idea.
-- Panharmonium: I got one of these recently, haven't had time to soak with it yet. IMO it's a super cool idea, and one my shop guys say isn't replicated by anything else identifiable (e.g. there aren't a lot of good alternatives). My sense is it is maybe not a great now or soon install for you because i) you're still getting into your first build ii) your current rack design is already full. My suggestion would be spend some time with your developing modular rig the next several weeks, then build a list of potential adds.
-- Mordax DATA: not in your build, but I really recommend this for almost anybody. Super useful for helping learn what the modules are actually doing. Stages and Tides would have been permanently baffling to me without the visualization from DATA. Bad news is DATA modules are hard to get. If you want one, get on a waitlist with your preferred vendor.
-- overall I recommend, to the degree you are continuing to edit your design, to focus more on a few priority uses. The idea is of course to have a setup that is great at 1 or a few key things, and avoids the danger of being diluted in purpose to mediocrity across most uses. This is not easy to pull off in a small to mid-sized design. I haven't really thought through your design module by module, but need to offer this "design pointer" for any new-ish person building a small to mid-sized rack. That said, your design (above) does seem to have taken several positive steps vs. your prior drafts.
You will have many more concrete ideas and responses once your initial modules show up and you start patching.
Good luck! Enjoy!!