Slantback, my point wasn't to discourage you from using high-back seats in the front of your car. I understand the safety concerns. My point was that there are many other high-back seats available at affordable prices that might not need to be recovered. As you said, re-doing these van conversion seats is going to be costly. I'm just suggesting that before you spend the money on these, take a look at bucket seats from a Mustang GT, Camaro, Honda, Acura and many others that can be bought on craigslist for pretty cheap and many are in really great condition. Most of these are a good size to fit these cars. For the back seat, you could recover the original with the same fabric/leather as the fronts (if you found some like you want). As 406Rich said, there are many affordable upholstery kits available on ebay designed to fit some of the seats I've mentioned.
Just trying to give you options, my friend. Obviously, it's your car and your choice.