Okay, here's a brief update. As I thought, I had indeed downloaded the five free styles that Yamaha MusicSoft had made available for the PSR-I455.
I haven't loaded any of them into my PSR-ERW400 yet and tried to play them, but I did look at the first style ("BhajanN," or "Bhajan NEW_3") in MixMaster to see the voices used.
One of the voices is for a special drum kit on the PSR-I455 (Voice Number 017, "Tabla Kit 2") which isn't included on the PSR-E models, which might be why the style won't play on the PSR-E453.
Two of the other voices do not even exist on the PSR-I455 (000-127-116 and 000-064-051), but I think they might be defaulting to GM1 voices ("TaikoDrum" and "SynthStrings2," respectively) when the style file is played on the PSR-I455. If that's the case, then they would probably also default to GM1 voices on the PSR-E453, and it would be a simple matter to just change their Bank Select LSB values to 0 so they explicitly select the GM1 voices.
However, adjusting the style file for the missing tabla kit is going to be more difficult, because I'll need to check every Note event on that channel to see which sounds are being played from the "Tabla Kit 2" voice, then see if equivalent or nearly equivalent sounds can be used from one of the available drum kits.
If I can get the "Bhajan NEW_3" style to work for my PSR-EW400, I'll post it for you, then check the other four free styles.