As far as Sting's TNA future is concerned, he is advertised to face Ethan Carter III at the TNA live event in Huntsville, Alabama on January 16th, which would be after his current TNA contract expires.
It's being said that Sting may simply be working a few additional dates with the company to allow them time to properly write him out of the storylines. At the same time, there is a decent possibility that he will sign on for another year with the company under a special agreement that has him working a limited schedule again.
The impression within TNA is that Sting will remain in the company due to the fact that they are booking their future with him in the mix. It could be a short-term deal but that is not confirmed.