a question about cooking temperatures for asparagus?

Yes, or you could put it in boiling water for 3-5 minutes until it gets really bright green then rinse it off in cold water and put it in a skillet with some butter, garlic, salt and pepper

I would just bump up the temperature for the potatoes. It will not make that much difference for 10 minutes. And the asparagus may cook a bit faster with the oven being that hot already. If you notice the potatoes getting a bit over done just remove them a few minutes early.

Yes, check it at 10 minutes but it probably needs around 13-15 minutes at that temp. Another way you can cook it by steaming it either on the stove top or in the microwave.

Yes, just cook it a little less at the 450 temp

That should work fine, but with all the other roasted vegetables I would steam them for a bright color on the plate.