Here's a full list of knowable parities based on the parities of our known variables, d and e.
-even e even d
-x – even
-a – even
-b – even
-f – odd
-c – even
-even e odd d
-x – even
-a – odd
-b – odd
-f – odd
-c – odd
-odd e even d
-x – odd
-a – odd
-b – odd
-f – even
-c – odd
-odd e odd d
-x – odd
-a – even
-b – even
-f – even
-c – even
The parity of n will be the same as BigN, which you can calculate from ((d^2+e+1)/2)-d. You can't, however, find the parity of n or N based solely on other parities. You have to calculate it based on BigN. So, for example, some odd e even d examples have odd BigNs and some have even BigNs. You also have to use calculation to find the parity of t, but this is a calculation based on unknowns, so it's a little harder than finding n's parity.