This isn't an all grain recipe it's for a partial mash.
I would find a better recipe if I wanted to do an all grain including pumpkin.
I've done Yuri's extract version and it turned out good and I received a lot of compliments on it.
I just finished moving my lastest batch based off of RichBrewer's pumpkin ale to secondary.
Rice hulls are only needed if you intend to mash the pumpkin...I just boil mine and deal with the trub. I think that Yuri said that even with rice hulls the drain was very slow but I don't intend to put word in his mouth so just shoot him a PM and he'll let you know.
I don't know how much brewing experience you have so if you've done a bunch of extract brews and are ready to take the leap then go for it but I wouldn't recommend doing a pumpkin beer as your first AG. It just adds a degree of difficulty that may serve you better to reserver to your 3rd, 4th or 5th AG Brew.
I don't say this to scare you away from the batch but your first true AG is kinda hectic to begin with and dealing with a stuck mash (if mashing the pumpkin) or trying to hit a volume knowing that you'll lose about a gallon of wort to trub just makes it a bit harder.