The way I see it I think DLC will play out like this
After Nintendo announced that Mewtwo would be joining Smash Bros as DLC Sakurai and his team spent their time working on Mewtwo and other pre ballot characters (like
). They probably at this time had already came up with the idea of allowing fans to vote for future Newcomer DLC. Then in April Nintendo announced the ballot when they revealed their first pre ballot DLC character; Lucas. They continued working on Lucas and other pre ballot characters while waiting for a good number of votes to pileup. They then released Lucas, Roy, and Ryu in June. After the first 2 months of gathering data through the ballot they began working on the first ballot DLC character in June while still working on other pre ballot characters.
If you think about it this makes a lot of sense because most fans voted within the first few weeks the ballot was out instead of waiting until the end.
Next in August they will release Wolf and a 3rd DLC pack of stages and costumes, and possibly showoff one last pre ballot character to be released in October. In August 4 months will have passed since Nintendo opened up the ballot to the public. Sakurai and his team will now reexamine the data again to see who is currently winning and pick their second DLC character from the ballot. Also, it is important to note that Sakurai and his team will now be able to focus almost all of their attention on working on just these two ballot characters.
October will come and the last pre ballot character will be available to download with the 4th DLC pack. This is when Nintendo will announce the first character from the ballot to be available sometime between December and February (that means Sakurai's team will have had 6-8 months to work on this first character). They will then in October look at the final data from the ballot and decide who the last ballot character will be and begin working on them while working on the other two ballot characters.
Two months after releasing the first ballot character they will release the second character, and then 2 months after that finally the third character. Thus, we will get a total of 3 characters from the ballot.
Obviously one of these choice will be the one and only