The consensus is the season filmed from late July to early September.
Lou posted on instagram on the 11th of August. Izzy returned to social media on the 12th of August. The two of them even poster pictures together stating they were travelling together. Hannah also was posting from the 15th of August.
It seems there was no restriction on use of social media from contestants who are booted pre jury. What we can take from this is that Lou, Izzy and Hannah were all definitely pre jury.
However many other contestants had social media actively that bounded filming dates suggesting they at least made the jury and therefore couldn't use social media until the game concluded. These people were Georgia, Mike, Sala, Shannon and Tom.
The remaining contestants either didn't post at all or I couldn't find them anywhere.
Anyway hope someone finds this of interest.