Sheesh...where do I begin?
Changing the input-Z will not make the tone from each output sound different. The "auto" setting will configure the Z for certain pedals only if they are first in the chain...and to 1M for all other models. Technically, lower than ~1M IN-Z actually compromises the guitar's dynamic range and attenuates the highs, but the pedals will sound more like the hardware versions with their "authentic' input Z setting. So, there's no harm in leaving the Z to Auto.
It doesn't sound like there is anything wrong with the "Fizz" version. It doesn't seem to be clipping. It just sounds like it has more upper harmonic content. That would indicate that the 1/4" output switch on HD500 face is not set to "line" like it should be when you are recording a line level signal. You should also make sure you are connected to the line ins on your Presonus A/I device from the main outs on the HD500, and not the Hi-Z guitar inputs. When reamping, you should connect from a line level out on the A/I unit to an FX return (set to line) on the HD500, and not to the HD500 Guitar or Aux Ins.
Also, the amp is the least spongy with the Sag at 0. That seems a bit extreme. Somewhere around the middle would be more amp-like. Same deal with the Bias X, but regarding amp distortion: amp distortion is the hardest sounding and least dynamic when at 0. It makes sense to boost the mids on the amp with the 4x12" Hiway cab. You may want to back it down after setting the Master DEP up higher. The Dyn 57 mic has a lot of presence and not much bass, so you may want to back the treble and/or presence off a bit. You might try one of the ribbons mics, the U67 or Dyn 409 instead. Just something to be aware of. The 57 may be just fine. They quite often are.
Regarding FX, you have the Output at 100 and the Drive at 0 on the Tube Screamer. I don't see a point in using the TS at all with those settings. TS's somewhat kill the dynamics and frequency range of the sound. They have their purposes, but I don't think it will help with the huge metal tone you seem to be going for. Moving along, the Gain on the last eq is at 0. I'd think that would drop the signal output a lot? Once you get your signal levels and amp set up right, you probably won't need the extra eqs.
Not that it will hurt to leave it, but I'm not sure why to aim for a -12dBFS internal peak signal level? Pro digital recording level is actually -18dBFS. You could aim for -6dBFS peaks all the way through to the recording without any problems. I always record around there. Recording to 32bit Float has no real advantage, but it doesn't hurt. The 24bit A/D converter would clip way b4 the file does, so you'd still essentially have a clipped file if it did. 32bit Float is useful for post processing.
For ~$380/pair shipped, I think the Equator D5 are the best "bang for buck" home studio monitors. Mix, SOS and EM mags all gave them stellar reviews. They are a ported coaxial design with internal DSP compensation. Bass extension, midrange clarity, and phase accuracy is outstanding. You'd really have to spend over a grand for anything more accurate. They are sold direct from Equator with a 60 day refund policy. I keep the input trim on my monitors down to -15dB, so I absolutely never distort the inputs. You either need to do that, or keep your A/I unit master output down ~halfway to be sure you don't get distortion. Break them in as with any monitors for a day facing each other with 180 degree channel inverted white noise up loud, but not distorting. Use them a lot in those 60 days to make sure they are OK. Power switching amps are less tolerant in some ways of spec anomalies than analog amps. If they were constructed OK, they should last many years if plugged into a surge protector. Don't buy balanced cables unless you need some more quality cables -- you won't notice the noise difference with short cable runs. Run signal cables perpendicular to power cables for the lowest noise. Make sure you plug your gear into a surge protector, or even a SP/PC/UPS combo unit. I got a Belken combo unit for ~$70 several years back -- good investment. Use the same outlet for all your gear to avoid ground loop hums.
Monitors should be elevated ~1' above the desk up to ear level when seated. I mounted ~1'x1' shelves of criss-crossed glued 5/8" thick finished poplar onto the back corners of my desk ~3' apart at the outer edges. I just use thick mouse pads under my monitors. I have a very complex shaped top floor carpeted bedroom area with a bed, thick folded linens and hanging clothes, and other absorbing junk, so there aren't obvious resonances. I hang a heavy blanket on the wall behind my head to kill high-end slap back. It all works fine. You could spend some money treating your room. It may not be necessary when close monitoring, unless you have significant echoes and resonances. A decent room is as least as important as decent monitors. You can check mixes with adequate studio headphones, but you should use a stereo monitor sim plugin if you plan to mix on them -- it has become a more common practice lately.
Guess I got on a roll and had to cover everything under the sun. Hope it all helps.