I like the idea of the spiced rum. I highly doubt you'll get much flavor of it in the beer, but maybe that'll turn out very nicely with just a hint of spices
Seems like it will be high in alcohol content, which might take away from the spice flavors. You should be modeling this off of an Amber, which it's highest OG should be 1.060, I would even see if you could get down to 1.055. I would just worry that when you taste all you'll get is a strong alcohol/somewhat cinnamonny beer. You don't want to overpower what you're trying to do: bottle pumpkin pie! The alcohol is just an added bonus
I would take out the candied sugar, which would lower your OG estimate. I'm not a big fan of using it in the first place. I've used it once and I think it should only be used if you're shooting for a very high ABV, and even so, there are other (better) ways to get sugar present. I just don't like the flavor it seems to put into the beer.
Good idea with the molasses. I may try that with my pumpkin ale.