Have you found your local clan and Ruus'alor Sol'cy? They are going to be your best local source of answers for your questions.
Its a solid and unique take on a Mando while not losing the correct aesthetic. The cummerbund however doesn't match the era of the armor you're wearing. Cummerbunds are only allowed in Post-Imp as that is the only era we have seen them in so far. The ab plate cannot be under any of your waist items once your kitted up and the belt seems to get lost in the front, not staying in place.
You've got some great dirt wreathing on those plates but the spacing is not quite there, you're close but there's a little too much space around the chest diamond. Remember no more then 1/2" from the CRLs. Your backplate also appears to be slightly askew which could be a result of your suspender rig pulling it off. I'd also recommend adding to the nylon padding portions of the suspender rig as right now it looks like unaltered earth gear. Maybe a few loops for shells? Or perhaps some electronic looking greeblies so it looks like a communication array? Lots of options to make that a bit more in-universe and kick your kit into the next level of awesome.
In terms of weathering you're a bit inconsistent. The plates look great but the softs are all so clean. The kama is even shiny! Remember you're entire kit needs to have the same level of wreathing across it. For someone looking at you they only get a snap shot in time. You just got done doing maintenance on your ship or finished a hunt. No time to get to the sonic to clean your softs yet, make'em dirty.
There's also a bit of extra fabric in the pants. You can really see it because of the thigh holster pulling it in on the one leg. Gonna want to tailor those pants in a bit so that you don't get the funny bunching and a nicer overall look.
The new gloves match much better! But again clean while the hand plates are dirty. I know black is super hard to see weathering on black softs so I suggest some lighter browns, greys and tans to help bring it out.
Oya on the attempt at building your own helmet. Not an easy task and sorry to hear it didn't work out as planned. This is a nice bucket too! There does look like there maybe a bit of a gap on the back of the ear caps? Might want to take a closer look at that bit. It also looks a bit big on you. Remember that you helmet can't be wider then roughly half your shoulder width or you start to get the dreaded bobble head look. Or would it be funko pop these days? Usually just tweaking the angle the shoulder plates are sitting at is enough to make it look right.
You're getting close! Keep up the good work and get tied into your clan and RS if you haven't already and they can help you make those final steps from UM to OM and make you a Movie worthy Mando!
I hope this helps! Looking forward to seeing you make more progress forward!