Neglible differences depending on psi.

For example, if you ran the 25's at a higher psi and have smooth roads you'd probably find the ride performance to be a bit more aggressive with increased road feedback and perhaps, even find that the bike feels like it's a bit more responsive. The latter probably has more to do with reduced rolling weight, smaller aerodynamic footprint, and the livelier feel.

Down side is, the larger tire provides a bit more suspension for the stoker and they, more so than you, might find the ride on a higher psi 25 to be a bit more harsh IF she's not using a shockpost and your roads aren't super smooth. Having lived in the Chicago suburbs back in the 70's I don't recall that our roads were all that smooth... lots of concrete roads with expansion joints and patchwork asphalt.

An easy way to experiment would be to move your 28 from the front wheel to the rear wheel next time your rear tire wears out and fit a new 25 to your front wheel. If you're happy with how the bike handles, that may be your answer. You can always move it to the back when the 28 wears out and see how your stoker likes it. If she is adverse to the 25, just replace it with another 28 and stash your 25 for re-use on the front when it starts to get a bit long in the tooth OR carry it as a spare.