As a designer, I would think the proper Kohler replacement for the Promenade would be the Kohler Tresham.
I have a little information on fill valves here.
Does the home have galvanized piping? Some of the fill valves have a screen on the incoming water supply, and if they gunk up, cleaning helps.
And by the way, TOTO has been the most trouble free product I sell.
And I do sell all the brands.