Rich Doughs

I'm going to be making pumpkin bread and I am making a preferment. I'm including just about everything in the preferment spices,pumpkin, powdered milk, butter, eggs and a small amount of yeast. I am excluding sugar and salt. Normally. I make a 100% hyd poolish with just the flour and liquid and a small amount of yeast. Does it matter that I included these other ingredients ? Can I still keep it on the counter overnight or must I put in fridge because if butter and egg ? Would I have been better off with just my normal poolish ?