Yes you can remove your signature now if you wish to do so. Tokens will be distribute within 1-3 weeks.
Please see the message posted on the signature thread:
https://bitcointalk.org/index.php?topic=2149054.120
"Hello crypto friends,
Final week stakes have been recorded and expected stash rewards have been calculated (see here). As such there is no longer any requirements to wear the STASH logo.
We are in the process of tallying up all Facebook, twitter and slack bounties. We will announce prior to token distribution.
We wish to thank everyone that participated in the signature campaign and believed in the project. Thank you "
And what about referral program? No prizes, no rewords?
Good question. How about referral program? And also twitter and fb capaign spreadsheets aren't updated.
All bounties, prizes and rewards will be finalised over the next 1-3 weeks and distributed. We will be making updates and public announcements in due course.