I agree with Galu. If you change the values of the components it will change the sound of the speakers. I think without understanding exactly what that change would sound like, I wouldn't do it. Just looking at the schematic, it looks like increasing that value to 33 uf would cause the midrange driver to crossover to the woofer at a lower frequency. That might cause a hump at the crossover point. One thing to consider is the designer also had the chance to make that value a 33 uf and would have saved a little bit of cost but he didn't do it. He must have had good reason.
And why are the tweeter and mid driver's plus and minus reversed compared to the bass driver?
To avoid a suckout at the crossover point because phase shift caused by filter plus acoustic phase relationship of the drivers themselves.
Sometimes it will and sometimes it won't, depending on what the crossover itself changes. To be clear, parts of the crossover network may only change the balance of the speakers and not the cross itself. In that case you can include corrections in your normal EQ routine.It's only 4uF less.