Can shrinking temporary TEMP tablespace in Oracle cause any harm?
all the three options would work, but would prefer to use first or the second one in production environment to avoid queries failing post activity due to not enough temp tablespace. Would recommend identifying the usage history pattern using queries similar to the one defined in this blog and then use that for your keep size.
https://zukus.blogspot.com/2016/06/temp-tablespace-usage-history.html