I could honestly talk myself into inclusion happening tomorrow or Wed Sept 2nd.
The more I think about it I could see a scenario play out like such......if the speculation about the dividend part and shorts is actually true:
Tesla and S&P have been in talks. Tesla is unwilling to dilute at the current stock price so they announce this dividend stock split, forcing a short squeeze that takes the stock up to $2,000 or higher(I personally would want something higher than 2250 for a offering price)...at which time Tesla does a small stock offering on Sept 1st to appease S&P and inclusion is announced after the markets close on Sept 2nd. The stock offering would be the same percentage of shares as pre stock split but because the share float is much larger from the stock split, the total number of shares in the offering "seems" bigger than before. It would be window dressing for sure, but could be compromise in that it "appears" that Tesla is creating a larger number of shares to appease S&P but the dilution percentage stays the same to us.
Something had to have happened or been discussed in the background for Tesla to move up the stock split by nearly a month and a half.