You gotta hang on to the trip you're on
Just curious, say I have the church tile that allows me to spend money instead of influence. Two questions:
1. Can I mix the allotment? Say the cost is 5 influence, could I spend 3 influence and 2 reis?
Yes, It's in the building example on page 18 of the rules.
2. Can discounts (e.d. treasury cards) be used to effect this? So if I had a -2 reis discount, would that previous example be 5 influence, or 3 reis?
Yes, see this thread