ToD DC doubts...

I'm playing on hard mode on 1st time (Best Tales of 2D)...

Can I play on evil mode in Lion's Side when I finish the game or I will need a clear save of Lion's Side? I want play after Lion's Side on Chaos mode in Stan's Side.

Can I carry items for next new game+ like the herbs and equips?

Yes, whetever you clear Stan Side or Lion side it adds to the number of times you completed the game and you win Advanced Gate (what replaces the Grade Shop).
Consumables and equipment don't carry over.
I don't remember for key items.
The monster book, food book and compendium carry over automatically.
You title list carries over too but to equip a title you'll have to unlock it again (unlocked titles will have a different color).

Thanks.

So the herbs atributes will be lost... =/

Yes, herbs attributes will be lost.
Just like in pretty much every Tales games.