USAA $1000 rebate only available if you purchase your X5 thru USAA Federal Savings. I couldn't find the $500 rebate for a lease that USAA used to offer.
The BMWCCA rebate is available even if you apply the USAA rebate. The 'rules' changed in July. If you purchase a 3-year membership, you're immediately eligible for the rebate, no 1-year waiting.
https://www.bmwcca.org/rebate-update