Tahoe or Yukon lease questions

Looking at leasing a Tahoe or Yukon I understand you guys want me to do the leg work and I will just would appreciate walking through it before approaching the dealerships.

Looking at one like this Tahoe

@chevysalesgirl was nice enough to send me the rebates currently being offered not sure if its ok for me to post that here?? I appreciate the help and do not want to upset anyone.

So to start out everything I would think sales price is important do I start off comping the vehicle on edmunds or kbb?

Once I get a better idea on sales price should I call or email these dealers and let them know I want a price based off the lease see what they offer and start working it based off what they send?

On a side note our costco membership expired last year can I just renew to qualify for that discount?