The great thing about the Norns are that they are super flexible. Moreso than the Sonias I think, if only because they go by color rather than type.
GZL and Liu Bei can both be used together if you ever roll them. In fact the big whale team I've seen is: Verdandi/Liu Bei/Liu Bei/GZL/GZL/Verdandi.
You can go two prong, or rows, or both. You can also ignore the whole fire sub element thing. You'll have less HP but it isn't too huge a deal probably except for some dungeons.
Verdandi/Sasuke/Artemis/GZL/Avalon/Verdandi sounds good.
Crunching the numbers in PADGuide, at max level and everyone +297 you have: 34k HP, 3.8k RCV, a whole fuckton of orb change, 8 skill boosts, 4 green rows, 4 green enhance, 60% skill bind resist, 6 two prong. Sounds really good.