Do Sikh women wear hijaab? What do they wear indian scarfs and panjabis?

They do not.

Extremely religious (Khalsi Sikh) women wear a turban like their men, but otherwise a regular Sikh woman would only cover her hair in a temple.

There is no relationship between Sikhism and Islam other than that their founder Guru Nanak started out as a monotheist with Muslim leanings...

The apparent commonality between Sikhism and Hinduism is cultural only, since one believes in one God and the other in many.

No hijab or veil wearing isn't allowed in Sikhism...Guru Amar Das Ji condemned Veil Wearing among Sikh Women...

Yes although while driving scooter,scootie or activa it is common for women to cover there mouth so that not to have dust or dirt go in and

Yes dupatta is common among Punjabi's for modest clothing...mostly women wear Dupatta with Punjabi suit

Baptized Women might wear Dumalla style-turban which is worn by both genders who are baptized but hijab isn't allowed in Sikhism

no, they usually wear a light sari covering the head if they are at the Sikh temple, most sikhs don't cover their head at all otherwise. It's a very progressive religion and completely different from Islam.

You seem a little confused, a Punjab is someone from Northern India where the Sikh religion is very popular.

Sikh women wear a turban, similar to how a Sikh man wears a turban.

Here are some pictures:

http://www.sikhiwiki.org/images/f/f2/Sikh_Women.jp...

http://31.media.tumblr.com/tumblr_m7rh3qvwvq1rsbjk...