For better communication I suggest TeamSpeak, Skype or Discord. Talk about stuff, much easier, than trying to write about it.
If you are the host of the game, you can do a lot of the stealing stuff, while they are offline. You will have full control about their characters and check their equipment for yourself. The good thing is, in Explorer mode Equipment should be hardly an issue.
Also it seems like your group is missing a dedicated trader?
Regarding your partners they are obviously playing for different reasons like you, so they seem to be a wrong match up for 'living the story'. But on the other hand Larian sadly kind of killed the cooperative gameplay with they try to make competativeness gameplay possible as well. There a now more group conversations with NPCs and such stuff, which makes your group feel less like a group and more like 4 people walking in the same direction.
