You can buy all the trekking gears like shoes, pants, cap, socks, gloves etc in KTM or Pokkara. There are plenty of shops there, and depending on your bargaining skills, most of the time, you will get cheaper price or better quality compare to in SG. Just dont be too fussy about the brand and outlook.
The only thing you need to get from SG are maybe local snacks, medicine, vitamin C tablet or Ribena and water purifier, if you dont want to keep buying mineral water there. Hot water is not cheap at base camp. I am kiasu kind of people, i even purify hot water..

If you get diarrhea, your schedule will definitely be delayed. Do buffer one or two days in Pokkara, just in case your schedule delayed. KTM is dirty and dusty, staying in Pokkara is much better.
You can eat meat during the trek. Indeed, their momo (dumpling) is really nice. However, beyond Chomrong, no much meat you can eat, only vege. Eat more while it last..
Lastly, do some exercise in SG before you go, like climb 10 floor HDB 5 time a day..
