I know it was written more than ten years later, but Shadows of the Empire addresses most of those issues you brought up, Shadowheart. According to that, they had quite a bit of contact, and planned it all together. At the end of Shadows of the Empire, Luke is at Ben's old place recording the message for Jabba, Leia and Chewie are off together on their way to Jabba, and Lando had gone in sometime before. I suppose Shadows of the Empire has slightly more credit to it than your average EU, since Lucas was more involved in it. It wasn't just one book planned and written by a single writter, but a multimedia project including an action figure line and even a sound track. Also the fact that Dash Render's ship The Outrider makes a cameo appearance in the SE of ANH also seems to give more weight to it than your average EU. A lot of people hated Shadows, I loved it. The book may have not been the best written, but the story was great and really flowed well with the OT so well that if you didn't know any better you might think ROTJ was written after it. The PT couldn't even manage to do this.
For anyone who has not read Shadows of the Empire, I'd highly recomend going to your public library and picking up the audio book. It is well read, and the abridgment actually improves on many of the novel's weak points. To me, the audio book is the definitive version of SOTE. The video game was pretty awesome too, but the N64 graphics are very dated today.
I hate Shadows of the Empire. I call it Shitholes of the Empire. The whole thing comes off like fan fiction and it's full of Mary Sue-ish characters. Starting with Bash Fender or Hash Vendor or whatever -"Look, isn't it cool our character's hanging out with the Star Wars heroes and he even fights in the Hoth battle and has a ship that look like the falcon and isn't he a great stand-in for Han?!!!" Then Xizor -"Look, our villain can rival Vader and he turns Leia on!" And Jix -"See our guy being casual with Vader. Isn't he cool?!" All these "cool" characters don't fit with the mentality of the OT, they have a lot in common with the "cool" characters of the PT, in the way the shove their "coolness" in your face. Guri's designed to appeal to fans who want to screw a robot. And the comic's Boba Fett fixation is more pandering to fans. I'm of the view that Boba Fett is overrated and the last thing I want is a story going "Look, isn't he the coolest dude in the galaxy?" The OT didn't push coolness like that. Shadows doesn't fit with the OT at all.
Xizor annoys the hell out of me and I hate that they make Leia subject to his sex control or whatever. I hate when people do that to characters. I don't think the real Emperor would give Xizor the time of day. And they ruin Leia's bounty hunter disguise by making it not her idea or the idea of the heroes. If Shadows wasn't presented as if it was the real story of what happened between the films I might find it easier to take, but it sets itself up with a big boast and then delivers annoying fan fiction. It annoys the hell out of me. And the Shadows elements in the Special Edition are another example of the special edition shoveling crap on us. Hash Vendor doesn't belong in the OT.
Shadows comes from an era when they were selling the tapes of the OT as the last time the OT would be available in its original version and when Lucas was mutilating the OT with the special edition. I think Shadows fits right in there as one of the crimes against Star Wars. A lesser crime maybe, but a crime nonetheless. No way can I accept that fanfiction as what happened between films in the OT.
By the time Shadows came out, Star Wars had already begun to go wrong and I think Shadows is a symptom of that. Heck, I think they started work on it around the time Lucas started writing TPM. Synchronicity of decline. November 1994 was when both of those things really got going. So the start of the OT's backstory being rewritten as a story about a dork complete with cartoon characters came at the same time as they were developing the idea of forcing in fanfiction between ESB and ROTJ.
(Sorry if I'm beating on something you like. Shadows just pisses me off bigtime.)