Sorry, I can't really help. Never made a pumpkin beer, so don't know what to do with the pumpkin (does it need mashing or not) or what really goes with it.
I'm not a fan of spiced beer either, so can't help with the quantities or when best to add.
If you are just going to toss the 1 lb of 2-row in the 5 gallons and steep, you are wasting your time and money. 2-row needs to be mashed. To mash it, you would need to add it to 1.5 quarts of 160 F water and hold it somewhere between 150 and 155 F for about 30 minutes. Then rinse it in 170 F water.