You said that your husband does the longer commute at 20 miles (40 RT). That would be the prime target for the Leaf rather than the Prius because it will cut your fuel expense the most. If the Leaf ever got to where it did not do the RT commute for him you could then switch to him using the Prius. With the 2016 and newer Leaf having the 8 year/ 100K miles warranty, you could get the pack replaced as needed and keep it several years past the warranty.
I bought my 2015 SV specifically to use on a 54 mile RT commute, which it did great even in the winter with snow on the ground.