I like the idea of different enemy types doing effects, especially if you need to save up items to deal with them.
~As far as starting scene goes, distinguishing higher difficulty with a higher ratio of total scene makes sense, it's just as you said, that between extra bonuses from prestieges and bonus xp, you can still start as a bit of a monster, I'd personally suggest adding on the character's starting level, that way the bonus xp a character has influences where they start directly, but the level would still be low enough to build up some items.
Poison I've actually found quite deadly in some circumstances being as it does continual damage, another reason why I like the idea of poison being enemy specific. Curses are more an annoyance, but can be a true hazard at really high levels when your trying to use an uba trank on something.
With respect to pack ordering, I wouldn't recommend sorting items by name, since then you'd have similar items changing all over the place, EG breezy cuffs at the beginning, but your windy cuffs right at the end. Likewise, I'd not personally be a fan of sorting by level, since I wouldn't want to need to tab through gear to find consumables or visa versa.
I personally liked the order as it was before, with most recent at the top, that way when you pick up a new piece of gear and want to equip it you can do so straight away, and only need to sort through the inventory when your looking for a specific consumable or selling to the merchant.
If you wanted something more complex, perhaps allow several sorting options available in settings for the player to choose between as they wish.
You could also consider adding a few filters for the pack towards the bottom such as show gear, show all or show items, though I don't know how complicated you want to get with the interface there.
Our souls with high music ringing; O men! It must ever be
That we dwell in our dreaming and singing, A little apart from ye. (Arthur O'Shaughnessy 1873.)