Antec 302 fan setup question

Hi, sorry if this is a noobish question but i'm about to put together my first build...

I have the Antec 302 case and an Asrock H77 Pro4/MVP motherboard.

The case comes with 1x 120mm fan (3 pin power + external toggle switch- hi and lo settings) and 1x 140mm (3 pin power + external toggle switch), both of which are exhaust. They are Antec TwoCool fans if you buy them separately.

My mobo has case fan headers for 2x 3 pin and 1x 4 pin. It also has 1x 4 pin and 1x 3 pin cpu fan headers.
The 4 pin and one of the 3 pin case fan headers support fan control, per the manual.

My questions are:
1. should i get another fan for intake (there is room for 2x120mm fans on the front)? i am not overclocking anything. my specs: i5 3470 + stock cpu fan, xfx double d 7870.

2. since the stock cpu fan only uses the 4 pin cpu fan header, can i plug a case fan into the 3 pin CPU fan header?

3. do 3 pin headers support fan control? I thought they had to be 4 pin to send that signal.

4. does it matter where i plug in my stock fans, since i don't think they support PWM anyway and already have an external switch?

thanks in advance.