One would hope so. Again, the necessary info is in the WT32i datasheet. It says (page 13) "VIL input logic level high" should be between 0.625xVDD and VDD+0.3, where VDD is the supply voltage, or 2.5V in this case.

So.. 0.625 * 2.5 = 1.56V is the minimum, and we should treat VDD (2.5V) as the best maximum. Anywhere in between could work, but the higher the voltage the better it ought to behave with faster changing signals like I2S. So I would guess that anything over 2V would be good enough.

The only question is, have we got the overall resistance values too high? Would 2.5K+5K be better?

Undoubtedly a real EE like Patrick could tell us, but I prefer to just fry try it!