How many crew members that Straw Hat should be? In very first of episode, Luffy said that 10 peoples are enough for his crew.
But I'm little curious, by 10 he mean, is 10 including himself or 10 other peoples on the ship plus Luffy?

I've read somewhere (I can't remember where I read, or even this is true or not) that Oda have stated the next crew is some kind "old enemy" of Luffy.
I don't think that Jinbei is the person that Oda said because he is not an enemy for Luffy at all (Once again I don't even know that Oda really said that old enemy thing).

So, I just want to know if Oda really said something about that old enemy of Luffy, and if so did Oda also stated about Straw Hat crew members are 10 including Luffy or not?
What the initial quote was "about 10 people" so there is no hard and fast rule regarding the final size of Straw Hat Crew. 
I'd like the theory of 4 more people joining. 4 (Zoro, Usopp, Sanji, Nami joined in East Blue), + 4 (Chopper, Franky, Robin and Brook) in the first half of grand line

Among the next 4 I am thinking Jinbei is a given. That makes 10 but I'd like to think some other allies such as Caesar, Vegapunk etc. may also join. There is this really vast theory about the following members joining which draws parallels between the previous joinees and the future recruits


   Jinbei, Smoker, Unknown Warrior probably from Elbaf and Tashigi. I liked it especially since it filled the "old enemy Smoker" and another female recruit as well as a fishman. I also agree with the theory that Luffy's garp is Coby. 


About Oda's quote, Unconfirmed rumours are floating around for ages. Next recruit is an old enemy, next recruit would be a female (Cue why people wanted Monet with Logia powers or Baby5) etc. etc.

http://www.marineford.com/Thread-One-Piece-Eiichiro-Oda-Interviews-Statements
This is a compendium of Oda's interviews that I find is well researched.