I have the Diamond Edition of NWN. And i have no interest to buy EE to play DOD. 30 Euro are to many for a Extension that become only 3 stars.

The enhanced and extended version sold here on GOG is not compatible with NWN's Diamond Edition, no. But you can still play the old, pre-EE version for free (link). IIRC, it doesn't have voiceovers and some other things that the new version offfers, but it's still a complete module.

(The same applies to Tyrants of the Moonsea, btw.)

thank you:)

I know, this is a better beta-version. But what i see... i think not, that i buy the dod-extension later, even less the ee from neverwinter nights 1.:(

PS.:
If it possible to play Neverwinter Nights 2 with only two henchmans? i mean, have i still enough firepower to solve problems with "aggressive negotiations"?
I have problems to control partys with more as 3-4 members. So i prefer smaller partys.
Same questions for Baldurs Gate.

You can have as many party members as you want. Sometimes you'll be forced to have a particular NPC in your party, but that's not a problem when it comes to party size. Remember only that the game will be significantly harder if you decide to reduce the number of NPCs in your party. It's the same here. You can even solo BG1 and BG2 if you like. But it'll be quite hard and can be impossible to finish the game if you choose a bad class. With two party members and on lower difficulty levels you should be able to finish BG1 though.