
The Scarpa SL should cover all your trekking needs during the trip. I'm not familiar with the Helium shoes.
I did a one year back-packing trip and took Scarpa SL, Merrel trainers and Teva sandals.
Foot care is important. Take medicated talcum powder such as Mycil, wash your feet at the end of your days trek and apply the powder and air your feet to dry (Teva sandals are good to wear after the day's trek).
Socks are very important too. Buy some Bridgedale Liner Socks (they are a thin pair which protect the feet) then on top of those wear a pair of Bridegdale Walking socks. This will prevent blisters and aid the removal of sweat from your foot to the boot lining. They are expensive socks but superb value as they last for five or more years even with prolonged use. They are superbly effective and during a year's trekking I did not have a single blister.
I spent one month of that trip in China and was there in winter. I visted Yangshou, Xian, Beijing and Hong Kong. Mongolia and Tibet look amazing places to visit for trekking.
Have a fantastic time! Good luck