Man I loved reading through this thread and seeing your build progress! It kind of reminds me of mine! Different truck, but same slow progression through truck to truggy back to a truck again lol. My son recently picked up the Knightrunner, so I of course as handy dad, was looking into your build so I know what things he should and shouldn't look into.
He's currently feeling out larger tires so hearing about your tire and rim experiences is definitely helpful. He wants to go as big as he can without having to trim anything at all. So I'll note that 4.6 may be just a bit too big. Definitely skipping the Hyrax...however I did a very similar thing with my truck by lightly trimming the fenders to fit bigger tires, then eventually just shaving them off completely.
Keep up the great work and pictures! Glad to see that ugly Ultron body got replaced with something more worthy! Man those creepy futuristic sad abomination of an FJ Landcruiser are ugly.