Huf formation and tax on gifting

I have few queries regarding HUF formation and procedure of gifting.

In my family we are Four individuals, Myself, my wife, my daughter (married), my son.

I am a senior citizen and retired having no income apart interest earned from investments of my savings for retirement.

1) Is HUF deed required for applying for a HUF Pan card in the name of Karta ? 

2) My Parents are no more, so can I gift money on my own and form an HUF ? if not then what is the alternative available apart from taking gift from relatives. Can I get alternate format of the HUF deed ?

3) Can I as well as my wife gift some part of our savings to HUF by way of cheque ? Is there any limit for the amount which can be gifted ?

4) Both my son and daughter (married) are earning. If they gift money by way of chque to HUF, will it attract any tax implications.

5) alternative to my question at point-4 above, Can my son and daughter (daughter) gift money to me or my wife as an individual and then any one of us can gift it to HUF. Which option is tax free, point-4 or point-5 ?

6) Is gift deed necessary everytime if the gift amount of more than Rs.50,000 is gifted to HUF or to me from my son or married daughter ?

Thanks.