If you
really want to sleuth what kind of things end up in EHI's fleet, one thing you can do is visit their used car sales site where they sell used cars from their rental fleet.
https://www.enterprisecarsales.com You won't see
all the possible vehicles, as some of their rental inventory, especially for higher end vehicles, are leased.
For the Fusion, by searching the site, you'll see that there are two models available, each with various trims. You can quickly exclude the Fusion Energi however, as the Carfax for that vehicle indicates that it was not a rental, and it was either bought by Enterprise at auction or from a trade-in.
Of the Fusions, there are several Trims, 1 S Sedan (which was never a rental according to its Carfax), 9 SE Hybrids, 179 SE Sedans, 5 Titanium Hybrids, and 67 Titanium Sedans. If you figure that these numbers are somewhat representative of what's currently in the EHI fleet (and exclude the 1 S Sedan), that means EHI's Fusions are 3% SE Hybrid, 69% SE Sedans, 2% Titanium Hybrids, and 26% Titanium Sedans.
You can also usually bet that the higher end models (Hybrids and Titaniums) will show up in higher proportions in the National fleet, while the lower end models will end up more at Alamo or Enterprise. Of course, there are always exceptions, since cars are shared and one-ways sometimes take cars out of where they originally started at. For instance, I currently have a Fusion SE Hybrid on an one-way Enterprise rental that was parked in a National parking spot at the airport I picked up from.