Water pump specs are rarely posted, just size of freshwater tank from which water pump draws. You can be sure the manufacturer will just install the unit that minimizes their costs, my stock Sureflo is still going strong after 9 years and is used extensively even when campsite provides water.
When looking at matching a tow vehicle to a particular TT, it's more advantageous to look at the GVWR of the rig you intend to tow. The empty or dry weight is subjective anyway. Although you may not load to the GVWR, anything less becomes added safety margin if tow vehicle is properly sized.
I don't have the specs in front of me (available @trailerlife.com) but I'm sure someone is towing similar. It would be a load for the Excursion no doubt, and towing comfort would not be ideal. Climbing hills and accelerating onto highways may prove challenging for this combo.