Yep! I'll go in order...
1) I reduced the chances of items such as elven/dwarven to much lower chances, rather than a 1 in 3 chance at the max level for the lists, it maxes at say, 1 in 10. Items such as glass and ebony are reduced to the highest chances of 1 in 30 for glass, 1 in 60 for ebony. In contrast, the actual level requirements were dropped by ~2/3rds. So a piece of glass can drop as early as level 24.
This isn't the ideal solution, I don't think, on a second approach. I think the level requirements shouldn't be modified all that much, but the rarities only modified.
2) It involved changing some AI settings (GMST's, really) alongside adding them to the inventories. There's some modifiers for it, at what percentage of health they start considering to use a potion, what the delay is between multiple potions, etc.
3) Sure! All of it's GMST changes. At the time, they were hidden and hard-coded in the exe - apparently, this time around, they decided to allow the CK to edit them so it's available. There's about ~100+ of them or so I modified in various ways. Omnomnom25 had some great testing results on them that I could pass on to you in a more concise form later.
4) (sneaking) Yes.

You can search my plugin for those.. if you open in tesvsnip, they're towards the bottom, not sure in the CK. I'd list them off, but I don't know them off the top of my head, been a while since I changed them.
The progress chart's changing a bit.. I'm going to change my focus a bit, centering it towards customizable changes, working into other mods. My battery's almost dead, on my laptop, so I'll say more later.