Two Proprietorship firm one has GST second doesn't

All the proprietorship firms under single PAN will have to be reported under single GSTIN, so better go for second alternative...

yes the aggregate turnover will be counted from all businesses from single PAN so turnover of both firms will have to be shown even though one GST number can be taken and business (goods or service supplied) of both firms may be added in that including showing the additional business place.

Both the firms are included in GST. However, if you are eligible and interested, you can opt for Family Business and can opt for HUF. HUF will be treated as a different person