These are all reasonable suggestions to me.
Regarding shared inventory for party members and staying true to encumbrance rules as written, it is still possible to do this via pooling excess available carry weight beyond what individual characters have equipped. And there's always the option of going for quick access inventory slots to represent items characters carry on their person, vs. the supply of items the party carries to replenish their personal supplies with.
Additionally - I think plenty of items in the game should automatically go to "wares" without needing to be manually marked as such, ie. any item with no purpose except bartering. Further down the track as characters get kitted out, it would also be handy to do things like "designate all non-magical items as wares" with one click from the equipment section of the inventory.
I'd also prefer it if "wares" just turned up in the separate section of the inventory without the "to sell" watermark (and no longer in their original section at all). Particularly if my suggestion above is implemented - I still wanna be able to look at that lovely emerald necklace before I sell it if I want to, I just don't want to manually have to go through and mark items individually as wares when it is clear that is what their purpose is.