This one does not have the part screwed into the hub, it has springs on both sides.

I'm not saying the ratchet screws into the hub, it's the part that the inner ratchet slides on.  The part in the original dt star ratchet system, big threaded ring on the left side of the picture.

I use Kingstop pads for gravel and MTB, they have a few compounds, I use the ceramic.  They're good all around, bite well, quiet, last ~2000 miles.

Unfortunately I don't have good news, hopefully someone else has some solutions.  The main issue is the bend in the handlebar, so an option could be to use a normal stem/handlebar (or externally routed one piece handlebar) and run the cables through the headset at a shallower angle.  Maybe there's a type of cable and/or housing that has less friction for tight bends, or a lubricant that can help.  I could never get mine dialed in so I went AXS.

165x42.5mm will not fit without the 120mm linkage, which the Vitus never used.  I was able to make rocker to seat tube contact without much effort.

Ha, I just responded to you on reddit.  Here's how my old Monstercross bike started life, I did a few rides with a fork and messed around with different tires, but mostly had it set up as a 29er gravel bike https://chinertown.com/index.php/topic,2837.msg20146.html#msg20146

Chainring clearance is limited by the chainstay.  MTB's have the wide tires that road bikes don't, so the chainstay flares outward where the tire is.  Bigger chainring means you need to push that little bump out rearward or inward, which means either making chainstays longer or limiting tire clearance.  In reality, 36t is probably the largest you'll find on a full squish.  The FM199 I built from had a bunch of chainring clearance, but it's a hardtail.  36t front and 10t rear is pretty tall gearing though.  Remember than 29er's are worth about 2t more speed than 700c, and 10t is 10% over 11t, so a 36/10t on 29er is similar to 42/11t on 700c.  Not enough gear to win a gravel race, but more than enough for XC racing and fine for most gravel stuff.  34/10t on my MTB's is enough to get around 30mph before I spin out and tuck.

Do you have an stl file for that bottle mount? I’d love to run a 2nd bottle on my L frame.

https://drive.google.com/file/d/1xMSEU1REAI_UqoaPSc10N6B0hA0j1nvj/view?usp=sharing

Yes you can use a zero-offset post, nothing wrong with that.  I will also add onto 2old2mould's reply that full suspension bikes sag more in the rear when you're going uphill, since the weight balance shifts rearward.  MTB seat tube angles are getting very steep because the terrain is often steep, which geometrically rotates the bike back and puts the saddle more rearward, and the additional rear suspension sag causes the saddle to shift rearward as well.  So it's not that 78deg STA is typically a good pedaling position, it's that 78deg STA ends up being more like 74, 75, 76deg when climbing. 

I'll add my experience, that I also like the steep STA of my FM936.  I also have a CFR707, and run the saddle in the middle of the offset post.  It's STA is still steeper than a traditional road bike, but not near MTB steepness.  But for me, it works very well.  Seatposts are cheap though, nothing wrong with trying out both kinds.  You can also just slam the saddle all the way forward on the offset post, and even though it's not safe to run on rough stuff, it'll give you an idea of what a zero-offset post would feel like.