I’m an sde1 at amazon but have 3.5 years of experience in all, 1.5 being at Amazon. Rather than sticking it out and waiting for promo here, is it smart to interview elsewhere and land a sde2 gig somewhere else? Is there any benefit of waiting for promo and then job hunting if I plan on leaving in a year anyway? TC: 155k
Leave of you're unhappy, unsatisfied or not growing in your current role. Don't leave to chase a title.
Most companies will only share your start date, end date, and title. Some will add whether you are eligible for re-hire (which basically means whether or not they recommend you but doesn't risk a lawsuit). As for when you should job hunt... Depends on how well you interview, how well you're doing towards a promotion, and how much you like your current job.
If you think you have skills for the next level, you should certainly interview outside and see how it goes. In best case you get salary bump and level bump. Otherwise you should be close to promo anyways, and will have more interview experience and preparation when you apply a year later.
Your title has nothing to do with your post OP.