I just called Avis to ask, was transferred to the PC desk. They confirmed the details mentioned above, and the rental count and spend count starts as of July 1st, no credit for YTD spend/rentals

The agent said the website will report what your count is, everyone starts at Preferred, then at 12r/$5k will be auto-elevated to Preferred Plus, and at 25r/$7k will be auto-elevated to President's Club

I have a rental beginning tomorrow, returning Thurs July 2nd, unclear if that'll be counted