Hi there to all of you

I have some technical question...
1. If NN5 is attached to ballhead, in this case there's no need for EZ-Leveler. Am I right?
2. I planning to buy NN5 + rotator RD16 + Manfrotto 055Xprob + 498 ballhead. Do I need any additional plate to attach my Nikon D300 to NN5 and then to 498 ballhead?

Thanx for answers
All the best