Hello everyone.

This post may not seem like it goes in the Dragonborn sub-Forums, but it is about Dragonborn as well, so bear with me.

I was doing some work for the Volkihar with a new Dunmer Assassin and Dunmer 2H, Heavy Armor tank that I've created. As I'm rolling through Radiant quests for the Vampires with each character, I get missions over in Solstheim locations.

Like "Kill the Master Vampire at X Barrow", etc.

Now the interesting thing is that neither character has killed the Dragon at Whitewatch Tower yet, so there's no way I can complete this mission. I've experienced this for multiple Radiant Quests including to get the "petrified remains of an Ancient Vampire", as well as "Kill the Dawnguard Agent".

I have not yet received any of the Quests to "Kill the Dawnguard Agent" nor "Blame it on the Dawnguard" where I dress up as one and kill someone important, in regards to Solstheim.

The reason I bring this up is that there is a minor debate going on across these Forums as to whether or not DLC can reference/expand upon each other, and I wanted to see if anyone else has been experiencing this since Dragonborn was installed.

You can go to Solstheim without doing the MQ. Speak to the guy at the Windhelm Docks. He will take you there.
The MQ is only required for dragonborn's main storyline, you can do sidequests and explore the island as you please without it.
Edit: And yes, thats normal. Radiant Quests from other DLC can send you to dungeons in Solstheim.

Interesting.

I didn't think you could go to Solstheim until you talked to the Greybeards... I may have to change my characters' career timelines.

You would not be able to start the Dragonborn main quest till you saw the Greybeards, but I would think they would still let you explore Solstheim. They would allow those who do not want to be Dragonborn to get something out of the DLC.

There's other proof dlc work with one another. If you have dg and hearthfire and become a vamp, you can get a coffin in the cellar. Small, but its there. Wonder if DB added anything homewise.

I don't think it works backwards. But it's possible. Also, I don't think you need Dawnguard for the coffin. Worth noting that any new plants in Dawnguard cannot be planted and farmed in Hearthfire.

I do know that in Hearthfire you cannot build a Coffin in the cellar unless you are a Vampire. If you're "alive" or something, then you never get the option.

Yep you can go to solstheim whenever you want just can't start the main quest until you talk to the grey beards. You just need to go to the windhelm docks and pay the 250 and your set.