Can't answer the first, but I can answer the second.
IWD2 is based on 3rd edition rules, while IWD/HoW are on 2nd edition. It's a pain in the butt changing 2nd ed chars to 3rd ed in PnP, and nigh impossible with the character creation system in the infinity engine games. Sorry.
(I was hoping to be able to import. I ended up writing down all my chars' stats from IWD's Dalekeeper, downloading IWD2's Dalekeeper 2, and copying the stats over. If you try this, I suggest you make similar level 1 chars, distribute stats and points and whatnot, save and close, use Dalekeeper 2 to give experience to match IWD chars, then re-open the savegame in IWD2 and level up.)