great effort in collating. On point 3, it should be the converse I thought - RM as a % of sales is higher at lower scale (since your bargaining power with supplier is lower) and in any case, PES being India based should have lower "other costs" than caeser stone which is based in israel/USA.
REquest you to look at PES financials and look at their fixed assets and see what they own, what they have leased and amortization of payments etc. Also, check on their environmental, Pollution control clearances.
I would not be worried on your concerns save for 1, 4 and 5. their sense of business seems to be all over the place - granite to apparel to granite to quartz
wonderful summary rishi - all said @sambath, if you can get a clarification on the origin, validity and expirty of RM supplies and environmental aspects, this story should hold. That's the most important part for sustainability of this.