Have you looked at the datasheet for the Max232? It shows a typical application. They used 1uf caps all around. I'd go ahead and use polarized ones at least for the charge pumps.
To reduce noise on most ICs it's always a good policy to connect up a decoupling capacitor which is tied from Vcc to Ground. A .1uf ceramic does the trick and they are pretty small. It protects the IC from noise imposed by other circuitry connected to that supply.
Hope that helps. Most of the issues you wouldn't see unless you had an oscilloscope. But the more complex your circuit is the more potential for noise there is and problems that crop up.
i'm sorry, i don't really get you abt Q.3. r u trying to say the best practice is to connect V+ and Vcc with a capacitor? or V+ to ground via decoupling capacitor(o.1uf)?