I zetad Vader,now what mods must i get for him to be viable in heroic rancor

TFP... for tenacity down. Otherwise you're going great to need 80%+ potency on everyone, in addition to the 200+ speed, which is also needed.

Just checked your characters. You need to get Tie Fighter Pilot to 7* before you will be able to solo it, and then you won't have to worry about being resisted. And, as said lots of speed mods on all of your characters.
I have my Vader geared a lot for potency as well to help in arena so his speed is low, but I still have no issues.
https://swgoh.gg/u/mzee/collection/darth-vader/

Given they just fixed the bug that enabled most to solo I'm guessing quite a few will no longer be able to solo using their existing Zader rancor teams. An unfortunate time to have just got him zeta... but he's great in many areas of the game so far from a waste. Time will tell with the latest bug fix.