Second this, I used this method as well. It helps if you don't take a minion master, to prevent the boss from accidentally being killed by minions.Actually there is now a 2nd method for the Dunes of Despair bonus that I've used. It works great if you have a full human team. If you have heroes it can be trickier but Ursen and I have done it successfully and I've done it a few times with full heroes.
Go thru the mission normally, but when you reach the mesmer boss that triggers the cutscene, don't kill him. Instead go around him and continue on clearing the way to the altar. Allow the ghostly hero to start the countdown then you and your team need to high tail it back to that mesmer boss and kill him. This will trigger the cutscene and move the ghostly to your location. Flag him there and he'll be safe while you kill the bonus bosses. You'll still have the 10 minute timer so hurry but it's very doable in 5 or 6 minutes.
As far as the other missions you need, just pm me here or ingame and i'll see which ones I need. I can do some of them with ya and I can help you thru a section of DOA as well. I just want to stress that I don't do runs. If that's what you want then you probably just want to pay a runner. I'll expect you to fight alongside me as part of the team.