None, Gheist have their best 2 star Arkn banned so fitting in 2 star replacements will be difficult and their 4 stars are fairly easily beaten by all the Montana and Uppers. Roots have DRs and low power so do not belong in DT. Piranas have really low damaging cards so they need a 4 round win 9 out of 10 times and Nightmare have Poison and + Life cards.
They really arn't the best clans for DT I would go with Sentinels, Uppers, Montana, All Stars, Bangers, Rescue or La Junta personally.
To answer your question about the best Soa and Sob combination for DT it would have to be Gheist and Nightmare but there are far better combinations else where.