The mods are workin in some capacity to archive important info. You'll likely just have to wait, or procure your own answers. Shit happpens. You might try posting the query here in the meantime, most people can't wait to try and flex some knowledge.

Likely because most making those builds are assuming you are running a primer, or are using weeping wounds. If you aren't using the combo-counter or a primer it's as you said, just inferior (in almost all typical use cases for melee).

They mentioned on Twitter yesterday that it was unavailable for some issue. I don't use Twitter so I dont have a link, but a quick google would take you there.

Hahahaha, glad to help! I switched mine around a couple months ago and have been enjoying him again. I run two blue shards for +energy-max, full umbral, hunter adrenaline, and a tiny bit more duration than primed continuity. I play him like a drain-tank and pop roar/iron on acolytes, it's a blast!

This is a bug that was introduced with Duviri's release. I made a bug report about it a couple hotfixes in, but otherwise haven't heard any feedback.

He's been hella power-crept out, no? Nezha has just been better Rhino since his rework as far as I know. Iron Skin is probably better/more comfortable as a panic rather than a preventative at this point (obviously without the ridiculous nonsense, as you mentioned). Roar is strong as hell, doesnt need much strength, so probably adaptation, grace/guardian, pop skin when hit hard or acolyte spawn? Sorry I don't have great suggestions. He has little actual scaling, and his energy pool leaves much to be desired :/

Sounds like a bug. Ammo-Case is supposed to be +25% max ammo, from memory. +200% would be amazing though!