Ultimate Adventurers + Chakra

1. I've heard Ultimate Adventurers (when they were first released) had less HP than their Adventurer counterpart at level 50. Is this true or just a rumor? If so, was it ever fixed?

2. Do Ultimate Adventurers share the same cash shop as Adventurers?

3. What exactly does Chakra post-BB do and how useful it is? I've read the skill description a number of times but still haven't been able to completely understand what it does.

Thanks in advance. :]