I have the same doubt!! nothing sure until Tamil TV Premiere of 2.0,might be Sun Tv or Star Vijay might be still in Talks to buy Tamil Rights either from producer or if possible even from Zee Network too.
As Zee Network doesn't posses Digital Rights of Tamil Version too,they may sell satellite rights if they get any Better deal from others.
There is a News about Lyca Productions the producers of 2.0 producing Rajinikanth's upcoming project to be directed by A.R.Murugadoss which is initially said to be under Sun Pictures Banner, If some give & take happens between Lyca & Sun 2.0 Tamil satellite right might shift hands.
Then very recently some of the Zee Studios songs such as from Movie Pyaar Prema Kaadhal started running on Sun Music and following that Pyaar Prema Kaadhal premiere that is announced to be telecasted last Sunday abruptly stopped.So Sun & Zee seems to be reaching some sort of agreement about some unknown content sharing.After Some more days we may see some content sharing between Sun & Zee otherwise its just a speculation.