From the wiki for what its worth:Uhh no. He waited 20 years on Whitebeard's ship and studied every Devil Fruit because he knew that being on the crew of the strongest man will increase his chances to get the fruit. That was not luck, that was smart planning.
How he got the Gura isn't known, so you can't call that luck either.
A chicken? Does a chicken storm a war filled with people like the Whitebeard Pirate's fleet of thousands, and then stand off against Sengoku, Garp, and make himself an enemy of every single one of the thousands of people there, including aforementioned Marines, the Whitebeard Commanders, the Shichibukai, hundreds of thousands of Marines and the Admirals with just 10 people?
Oda never said anything about strength. He said the number of the division crew doesn't rank authority. The Division commanders are all on the same level of authority. Ace can't tell Thatch what to do, Thatch can't tell Jozu, Marco can't tell them, etc. etc., unless one of them becomes captain.
Yes he was. Ace asked Teach if he wanted to be division commander instead of him, which Teach declined.
D: About the Whitebeard Pirates, if there are pirates from the "Whitebeard ally groups", is there a possibility of one of them becoming a commander of the real Whitebeard Pirates itself? Or are the commanders all from the real Whitebeard Pirates from the beginning? P.N. amanuts
O: Ok, I'll explain a little about the Whitebeard Pirates. First, captain Whitebeard and the 16 commanders. All 16 commanders, despite numbers and ages have the same rank. All the same. Whitebeard Pirates are just split in 16 groups and the division number does not indicate strength. The 43 ally pirate ships are not any part of the Whitebeard Pirates and are usually all just scattered everywhere living their own little lives. Yet they are loyal to Whitebeard, and help him in desperate times. They are like that. In Ace's case, the Spade Pirates were destroyed, and all the members joined the Whitebeard Pirates, so he was able to become a commander.
So no the number doesn't mean strength.