First AG can I make a Cream Ale into a Pumpkin

I really want to get a Pumpkin going so it’s ready for Thanksgiving. I will be doing a Cream Ale AG tomorrow. I am a AG virgin

The original recipe calls for:

7lb Rahr 2-row pale
.75 Gambrinus Honey malt
.25 Dingemans biscuit
1oz Mt. Hood
1oz Williamette

Since this is my first AG and wanted to hedge my bet with LHBS crushed grains and probable lower efficiency so I ordered an extra pound of the Rahr 2-row.

I have 3 cans of pumpkin and plenty of pumpkin pie spice, do you think this would make a good candidate for a pumpkin? Or should I leave well enough alone and just concentrate on my first AG?

I will be doing a batch sparge in a 70 qt w/ a PVC manifold.
I currently have a 1000ml starter going with Wyeast #1056

Seems like an adequate recipe for a pumpkin ale. Be carful with the pumpkin spice, what's in it? I like to use seperate spices I know I want in a my pumpkin ales. Like some cinnamon sticks, ground nutmeg, sweet orange peel and maybe some ginger if I'm feeling crazy.

It says:

Aromatic blend of ground cinnamon, allspice, nutmeg and ginger

I do have Cinnamon sticks and whole nutmeg.

How much of the PP spice should I add and when? I realize I can taste test and add more later but would like to get somewhat close.