Greg has hit upon it. The time to recharge the batteries from the solar panels will almost certainly not keep up with the amp draws. The max rating of the panels will be nowhere near what you'll get out of them on a regular basis. Plan on half of what the panels are rated for. On the other hand, the Espar will likely use far less amps than you think, unless your van just isn't insulated at all (then it will use far more than you think). There is the initial whoomp of 10 amps or so, but that's just for the first few minutes of boost heating, then it will quickly drop down and spend most of its time in the 2-3 amp range. The Coleman draw is minimal, so that's not a concern. The laptop will draw more than you think, since it will be drawing power to run the computer as well as to recharge the laptop's battery. It adds up.
But all in all, the panels should provide well based on your projected amp draws above. I would supplement the panels by charging the house bank as you drive (or via a generator), as that will be the key to keeping the batteries fully charged as often as possible.
Cobra isn't the best, but it's certainly not the worst. It'll do fine for what you will be running off it.