I have recently started the game for the first time with the Co8 new content installed and wonder about the
consequencs of hiring NPC´s and having them killed to get their stuff (e.g. that thief in the inn).

Are there any cnosequences? Do I become shunned if the daughter of that farmer (fruella) dies or Melany?
Do I miss later sequences in which an NPC would have appeared?

On gamebanshee only with Burne is a remark that he is involved in one of the good outcomings of the game.

Theorically you shouldn't have any problems teking their equipment when they are alive if you have the Circle of Eight pack...I played it recently with the 7.5 version and with some exceptions, that could be solved speaking to the npc, I could give/take anything from them and they no longer looted anything.
In the ending I saw there were references to your wife, so take that in mind.
Did you downloaded the normal or the NC(new content) version?. I played it with the NC.

I have the Co8 mod installed including the new content. And in the options I have "humble NPC´s" checked.

In the game however I can´t move all equipment from NPC´s to my characters.
e.g. I let the thief in the inn join and wanted to move his magic dagger and ring of invisiblity to my own rogue - that does not work as the NPC won´t let go of those items. Not even if he is unconscious...

*Normal* Items like his leather armour or his shortsword I can move without problems.

The same happened to me with Elmo, but there was an option talking to him that allowed you to take his axe from him, something like "give me your items so I can enchant them"...He never remembered to ask them back ;)
Perhaps the thief has some similar line of conversation?

As a related note, how do you get rid of dead NPC companions?
Normally you talk to them and tell them to take a hike, but they don't want to talk while dead. :(

Unconcious/dying party members go grey with a little [zz] icon on their portrait, when they're properly dead they should have a red looking icon over their grey portrait, clicking the red icon removes them from the party (you get a confirmation window).

You can then loot their corpse. Removing them from the party while dead means you can't resurrect them later.

Make sure to coup de grace your dying npcs if you want to get rid of them by 'misadventure'.

Melany had no idea I'd married (or killed) the obnoxious girl across the village from her, when I wooed her for her fathers sword. I didn't kill both girls, I just scarpered as soon as Melany's father handed over the sword, leaving Melany behind.

Thanks. I don't care about the loot, but the next time I play some of them are going to make the ultimate sacrifice to by me a few extra rounds in one of the early game tough fights.

There is one obvious consequence to killing NPCs: other NPCs. If other NPCs are in your party, they will object to your mistreatment of hirelings, in a most hostile way. It's fun to see it go down, though.