Since Pumpkin Pie is a custard-based product, it should be kept refrigerated. Do not leave it out at room temperature for any more than 2 hours, but less time is even better.
Rubbing alcohol is a very useful first aid product. It can be used for many different things. The shelf life of an open bottle of rubbing alcohol is usually a year, but check the use by date.
Cover and hold the cork with a clean kitchen towel, turn the bottle. You want to make sure that you turn the bottle more than you turn the cork and go slowly. http://www.cellarthief.com/_blog/Blog/post/Opening_Champagneand_Looking_Cool_Doing_It!/
No, the process of freezing will make the pumpkin turn to mush very quickly.
There are lots of tips, tricks and suggestions out there for corralling the bubbles. Most recommended is a special pressure-withstanding cap just for champagne bottles. You can do that, and/or you can pump out the oxygen, pump in carbon dioxide, place a metal spoon in the neck of the bottle, etc....