The current Federal tax credit for electric cars still remains at $7500. Once a manufacturer reaches 200k units sold, the amount for additional units sold gets lessened and eventually disappears. No manufacturer has reached that point yet, though Nissan is about halfway there and Tesla a bit over 1/4 of the way..
If you lease, you cannot take the tax credit yourself, as it's technically not your car. However, if the car is leased through the manufacturer's financing arm, the manufacturer can (but doesn't have to) pass all or part of the savings to the lessee in the form of a "Capitalized Cost Reduction."
"Cheap" electric car deals rely on this to keep the payments low. Nissan has done this for some time, as do most other electric car manufacturers. VW is currently doing this.
California's $2500 rebate is regardless if the car is bought or leased. All buyers and lessees are entitled unless they make over $250k/year, or have already claimed the rebate twice since 1/1/2015.