When there are several conflicting ways of storing seed from several sources, the answer is usually that all of them work.

I don't do pumpkin, but I do ornamental eggplant. Recommendations abound, most involving a refrigerator. Mine do just fine dried for a week on a plate, then tossed in an envelope and stored in the cellar for the winter (sixty degrees).

Seeds are surprisingly resilient things, and unless you plan on pushing the outside boundary of their storage time, perfect storage really isn't all that critical. Keep seeds dry, dark, and cool, and they're usually just fine the next year.

With the number of species I store (nine) and the number of seeds per species (many), the refrigerator simply isn't going to work. So compromise is necessary, using just those envelopes. For over the winter storage, that's not a problem.

Your pumpkin seed saving plan is perfect.

The three rose germination plans you mentioned have one thing in common: they all involve cold treatment to help the rose seeds germinate more readily. Of the three, I'm most familiar with is putting the seeds in moist potting mix in the fridge. It should get about three months in there. If you don't like potting mix in your fridge, consider putting the seeds in a moist paper towel in a Baggie instead. Any that sprout in the fridge should be potted up and put in light.

The peroxide is a pre-treatment, also to boost germination. The differences in soaking time are likely because peroxide isn't super-sensitive timing-wise. Longer times are for thicker seed coats, not sure how thick rose has.

I wouldn't let seeds dry out once they've been soaked, but that's just me.

Good luck, have fun, take notes and try a few different ways if you have enough seeds. I've learned that optimal seed germination isn't yet an exact science, but that's what makes it interesting. :-)