Tashahhud and ghusl

wa alaykum as salaa wa rahmatullahi wa barakatuhu!

Thank you for your questions! 

1) According to the fiqh text, Al-Mukhtasar al-Mufeed, which we translated as The Beneficial Summary, the obligatory part of the tashahhud is the shahadatayn.

2)  If by ritual ablution you mean the same ritual ablution for the prayer in that order, it is not an obligation. According to the same text, the only obligations for the ghusl are intention, rinsing of the nose and mouth, washing (which includes rubbing) of the entire body, and the penetration of water through the hair. 

3) As for the necessity of rinsing the private parts for one who has already rinsed them, there is a difference of opinion within the madhhab. One view is that the rinsing of the privates is a part of the wudu. Another opinion is that it is not (Ref. At-Taaj al-Mudhhab). 

Hopefully, this answers your questions. And Allah knows best!

IRS   

wa iyyak!

You would have to perform the ritual ablution for the prayer after having performed the ghusl. 

As for the differences of opinion, you are welcomed to choose one of the two. 

The Beneficial Summary is here . Several years ago, a brother recorded audio lessons on portions of this book. InshaAllah, they will be beneficial to your understanding. 

And Allah knows best!

IRS   

Thanks for your question! I'm sorry, I can't answer this question, as I am not a mufti or scholar. I'm a simple, humble translator. 

I would recommend you contact Ustaadh Mohammed al-Shareef (This email address is being protected from spambots. You need JavaScript enabled to view it.) with your question. 

And Allah knows best!

IRS